Hello, my name is John Kelly and this is the
WeberAuto YouTube channel. This is the fourth episode on the evolution of the Toyota Prius
hybrid transaxle as you can see sitting beside me here is a 2017 Toyota Prius Prime and then
on a hoist back here behind me, we have a 2017 Prius eco. the Prius behind me on the hoist and
this Prius Prime here are the fourth generation Toyota Prius here in the United States they
both use the P610 hybrid electric transaxle and there are a few differences between the two
since the Prius Prime has an electric vehicle or EV mode only where the Prius eco behind me does
not have much of an EV mode so let's go take a look at this new P610 hybrid transaxle. The P610
is a totally different design than the previous Prius hybrid transaxles but as I mentioned in
the introductory video to this series to really understand how this transaxle works you need to
go back and look at those other transaxles and how they worked and how they evolved because
you can pretty much see pieces and ideas from every one of those transaxles in this one right
here. now this transaxle as I mentioned is the P610 if you look right here on the side of the
case it says P610 there's a three-digit code the 1NM right there. this is the driver's side
case of the transaxle and this will be the front of the transaxle, this transaxle is part of the
Toyota new global architecture the TNGA system and what that system is is they are trying to make
everything more efficient smaller compact reduce weight this transaxle is the second lightest
Prius transaxle ever made at 179 pounds the only one that's lighter weight and this is the Prius c
transaxle which has considerably less power at 176 pounds so only three pounds lighter. this transaxle
is 51 millimeters narrower in the vehicle than the P410 transaxle that was used in the third
generation Prius so it's a smaller package it's lighter weight and as it turns out it has
more power than the previous transaxles had in the past so let's take a look at a few things
here first this is a fully assembled transact so we are going to totally disassemble it look at
the parks the components talk about the theory of operation and show you that it even though it's
a different design it still it works just like the previous model transaxle the P410 it's just
everything is arranged in a different location so here on the side of the case, we still have
the oil pump on the side case but it's inside the case now rather than externally like on
previous transmission transmissions we have an electrical connector right here where there are
two resolvers we have our mg one motor that's our starter motor for the engine and our generator
down here in this section of the transaxle then up here we have MG2 which is our traction motor
that propels the vehicle down the road so they're offset of each other this is called a parallel
axis transit transmission and it's very similar to the Ford hybrid transaxles in the 2017
Chrysler Pacifica the SI -eVT the single input electronic variable transaxle. they all have the
same parallel design here but as I mentioned in the introductory video this transaxle is highly
refined compared to the for the previous forward ones now Ford for 2017 has a new one that I have
not seen yet and I read that it has a new highly refined motor system so maybe they've done the
same same thing I have seen inside the Chrysler Pacifica one and it's a real nice transaxle
very powerful transaxle for a minivan this is got all the power we need for a small Prius but
you're never going to see this in a minivan you might see a larger version of it but this is a
definitely a small car transaxle alright another thing that's unique here on this trans axle if you
look right here we have all six three-phase cables for both mg 1 and MG2 coming up and they're just
these little tiny diameter wires and the inverter converter sits right here on top of the transaxle
let me grab that inverter so even this inverter converter does design the system is about 15
pounds lighter than the 3rd generation Prius inverter converter we have the inverter portion
that does the AC to DC conversions and the DC to AC conversions and then down in the bottom we
have the DC to DC conversion that takes place so that's the inverter at the top convert you see two
DC convertor in the bottom so this just sits right up here just like that in the vehicle and
you can see under the hood you can see this black cover seeing right here there's a label right here
that shows or that you can see under the hood and all of this is what's underneath it so it's it's
guys a low center of gravity in the vehicle which makes the vehicle handle better also but that's
the new inverter converter. It has an electrical connection just right here on the side all the
bolts for the three-phase cables go through there and there's a weather tight shield that goes over
it a couple of coolant hoses that the hook to it to keep it cool also but we won't concentrate on
the inverter converter in this video maybe later on I'll do videos on the inverter converters
alright if we rotate the transaxle around to the front view here you can see we have an
electronic shift actuator just like a lot of the previous Prius transaxles we have something
new to this p6 10 transaxle and that is a heat exchanger that's external to the transmission
now Toyota has done the heat exchanger that's external to transmissions on regular planetary
gearset style transmissions but up to this point on the other Prius transaxles, we've had coolant
that actually ran through passages in the trans axle itself that's no longer the case the oil
pump in on the side cover here will pump fluid up to the heat exchanger right here where we have
cool coolant from the radiator coming in here and then it goes through absorbs the heat from the
hot transmission fluid and then it goes out to the electric water and the inverter converter
and back through the radiator and cycles back in here the transmission fluid that gets cooled
down then goes up to the top of the transaxle right here where go through and splits apart and
goes to the stator assemblies of both the MG1 and the MG2 motors and cools those stator
assemblies and we'll take a look at how that happens here in just a little bit and what
those Stators look like if we look at the engine side of the transaxle you can see the clutch
damper assembly as Toyota service information calls it the damper assembly looks very much
like the previous transaxle ones it simply splines to the transmission input shaft which is
directly connected to the planet carrier of the power split device just like all previous Toyota
hybrid transaxles the clutch damper assembly bolts right to the flywheel I've got an alignment
mark right here right where I took it apart there's six bolts that hold it to the
flywheel and it rotates is one assembly now if you have the Prius Prime here in the United
States or Prius plug-in elsewhere then in-between, sandwiched in between, the back of the flywheel
and the crankshaft where the flywheel bolts is a special one-way sprag clutch and a sprag clutch
will allow the crankshaft to rotate one direction but not the other so the Prius prime uses that
because this transaxle in the Prius prime will use mg one to help propel the vehicle down the
road but it can't do that unless we can prevent the engine from spinning backward and it does
that with this one-way sprag clutch if we keep turning the transaxle here in the bottom of the
transaxle case is the drain plug to drain the Toyota world standard transmission fluid if you
need to check the transmission fluid level in your Prius you just remove this plug the engine does
not have to be running make sure your vehicles on a level surface if fluid comes out too much
fluid within it if no fluid comes out either it's at the right level or it's or it's low now these
instructions and service information say it can be a few millimeters lower than the plug here is
matter of fact on this transaxle it can be eight millimeters lower than the plug and still be in
the acceptable range so you can add fluid back in here until it's up to the top and flowing back
out, let up let it come out until it slows down to a real slow drip and then then you're full
there's also a fill plug right up here on the top if you use this plug to add fluid don't take
this plug out until you clean this whole area off because dirt and crud might get down inside of
the transaxle it's better to use this one here on the side there's an aluminum gasket and
these bolts need to be torqued in place that gasket typically is not reusable you're
supposed to replace it and then torque it to specifications to keep it from leaking all right
as we continue turning on the side here it's like nothing to see on that side and we're back to the
back to the side of the transaxle where we started all right let's start taking this thing apart to
disassemble this transaxle there are three case pieces that can be disassembled you've got your
rear cover and do not take that off until last the bell housing portion which is this section for
word is what we're going to take off first and so we're going to lay the transaxle on its side
and then that allows us to get to the final drive gear and the counter gear and see the gears that
both mg 1 and mg to connect to if we take off this rear cover then we can see the stator assemblies,
the rotors, the resolvers, the oil pump, and so on normally that's not a serviceable area you can't
buy parts for anything in there yep you can buy the half of the case and replace it on previous
transaxles right now I don't know what you can buy other than the whole transmission on this new
of a transmission but I suspect if it's just like any of their previous transaxles that pretty soon
you'll be able to buy pieces pretty soon you'll be able to buy service pieces for it all right so
let's lay this transaxle on it oh we're going to lay it on its back but there's a pressure cap plug
right here in the back that I'm going to take out because the whole weight of the transaxle will lay
on that plug, if I don't take it out when I do take it out then it lays on this rib right here
and it won't hurt anything so I'm just going to set that off to the side now I've had this trans
axle apart already and back together exploring cleaning labeling everything so these bolts are
all loose normally they would obviously be a tort you need to be careful with how you treat hybrid
trans axle then and any trans axle for that matter because there's electrical connectors and other
small breakable parts on there that you don't want to break they may not be available to purchase
or could be quite expensive or timely before you could get them again all right here on this on
the front of the transaxle we've got to remove our heat exchanger and our oil cooler pipes to
get this bell housing off when I disassemble a transmission especially when I've never been into
before I make sure that I bag up all the parts that go together in the same bag so that I
can stay organized there's a banjo bolt on the top of the transaxle here where the cool fluid
comes in where it goes directly to the stator assemblies to cool them okay so there's the pipe
for the cooling and then we've got the pipe for the oil pump to deliver the hot oil to the
heat exchanger there we go and the transfer tube energy careful taking these hoses off of here so
we don't break the aluminum heat exchanger there we go and the heat exchanger itself so once again
we have two coolant pipes one from the radiator with cool coolant goes through absorbs the heat
from the transmission fluid in the heat exchanger and then goes to the electric water pump where
then it goes up to the inverter converter to cool it and then back out to the radiator and
back here and then we've got two Inlet and outlet for the automatic transmission fluid on
this heat exchanger these aluminum fittings here can be broken quite easily or pulling on them
so be real careful with what you're doing all right we're going to bracket holds the cooler
line on all right now we have bolts they'll hold the bell housing down that are long and then
there are four more bolts that are short you can see right here these would be the short bolts
these would be the long ones because the case is thicker we have five bolts inside the bell
housing that also hold the case half together all right let's remove these bolts for myself I've
learned over the years from damaging threads that if you use an electric gun or impact of any
sort and you take these bolts out really fast you're going to the chances of causing damage
or much higher but if you take them out slowly to where the air gun hammer is not hammering then
you're not going to damage anything sometimes though these bolts have thread lock on them and
if they have thread lock is if you pull them out really fast with an impact gun it can and
usually does damage threads so you've got to be real careful with that it really depends on the
type of thread lock whether it's the low strength or the high strength and just two more bolts right
here all right the first time you try to split one of these cases, it does not want to come apart and
it doesn't want to come apart for two reasons one is there is a special Toyota Form In Place Gasket (FIPG)
sealer that makes a gasket between all these metal to metal surfaces, it was installed properly out
of the factory which means that both surfaces were clean and dry all the bolts were dried to
both threads were dry there was no transmission fluid anywhere to contaminate the sealing ability
and adhesion ability of this form and place gasket sealer or fitting as it's called which means it
really likes to stick when you try to separate the two case halves the other thing is there's
usually at least two alignment dowels that cause a real tight fit tight alignment to separate the
case halves anyway so as I've shown in previous videos we ought to usually give you someplace
to pry between to lift up on the case and so here's a spot right here you are not to
go in and take a hammer and try to wedge this into the in-between the case halves, you'll damage that
ceiling surface and then you've got a try attempt to clean that up so I've already removed the fit
back we're just fighting the dowel pins and any bearings that are inside the transmission that are
both are inserted into both the bell housing side of the case and the case half or the center case a
portion right over here on the other side replace right here where I can pry and I'll go back over
here to our previous prior point there we go all right in this Bell housing side here's
where torque clutch damper torque limiting quartz damper was but on the bell housing side
on the inside of this transaxle, we have several things to look at first are a ring gear in our
differential case set right here and it's going to be spinning in this direction which means
it's going to be flinging oil up and it will be hitting other gears and oil will end up
getting routed to what are called oil catch tanks oil catch tanks so that's a tank that's
a tank this is a tank here's a tank that has a cover on the front of it to help
hold more in and then it drips out this little hole right here there's a magnet down here
on the other side of this differential oil baffle to gather any metal parts that might
or any magnetic parts that might end up in the bottom of the transmission you can see we
have an input shaft needle bearing in here and then we have a countershaft taper bearing cup
here with a shim behind it to set the preload of the bearing our fluid level check plug is
right back here and I've at the top of this yellow sticker right here is the approximate
fluid level in the transaxle when you've got the proper amount of fluid installed all right
let's set this on its side here we will take the gears out of this center case half turn
them over and put them in the bell housing side to really see how this thing works here in
a few minutes but for now let's take a look at what components we have involved here now when
I took the case half apart a pin fell out that goes to the parking pawl this is the parking pawl
right here and it will engage with these notches right here on what's called the parking gear
so each one of these notches is a place where this parking pawl can go in and prevent this
piece from rotating so let me just show you it preventing it real quick I'll slide the parking
Pole back in place drop the pin there it is all right so right here is the parking
pawl and notice it's in a notch of this housing right here that we'll talk about
in a few minutes and it's physically preventing that gear from rotating the shift actuator
assembly here on the side of the transmission is what moves some linked parking linkage up
and down inside the transmission and makes that parking pawl engage or disengage from the
parking gear so this only controls whether you're in park or not in park there is no neutral there
is no reverse mechanically it's all electrically the only thing that's done mechanically is park
even forward is electrical okay so I'm going to remove the parking pawl and it's a little
pivot pin okay let's talk about the rest of the pieces here inside this transaxle we have
our differential case with the ring gear right here we also have our open style differential
that allows the front tires to spin a different speeds as you go around corners the P610 trans
axle right behind the side gear has a beveled plate that beveled plate preloads the gears
to get rid of any backlash that is normally there it's and it's supposed to be there it
also acts just a tiny bit like a real loose limited-slip differential another thing that's
unique about this differential assembly on the P610 is that there are no bolts that hold the
ring gear to the differential case this is a pressed on ring gear it's pressed on and notice
there are two different differential gear ratios here depending on whether you have the Prius prime
or the Prius so the regular Prius regular regular Prius has 73 teeth on the ring gear and 21 teeth
on the pinion gear that drives it, that's part of our counter driven gear that gives us a final
drive gear ratio of 3.473:1 but if we have the plug-in Prius version
the Prius prime then it has 75 teeth instead of 73 on the ring and 19 teeth on the pinion instead
of 21 which gives us a 3.947:1 gear reduction for the Prius Prime. now
at first I thought why did they do that and then I realized that when you are driving in
electric-only mode EV mode you do not have the additional torque of the internal combustion
engine to help you accelerate so I did some math and let me open that up here if we go back
to the third generation Prius and we look at how much torque the MG2 motor had the one that
propels the vehicle down the road and then we multiply that through its gear reduction in the
motor speed reduction gear set and then we also multiply that by the final drive ring gear set we
get a theoretical maximum torque of 1389 pound-feet to the tires now how does that compare to the other
Priuses the first Prius the first generation Prius was 1011 the second-generation Prius was 1213
the third-generation Prius is 1318 so 1300 approximately and then the
Prius only version of the P610 is also 1300 and one and the Prius Prime with this additional
gear reduction gives us 1477 almost 1500 pound-feet
of torque maximum torque you're not going to have that all the time that's just maximum combined
torque with MG2 propelling the vehicle now I do not believe now it doesn't that does not include
any additional torque of mg one helping to propel the vehicle under those certain conditions so
it would be even higher with that now none of the previous torque ratings I gave you included
the torque from the internal combustion engine so the 1300 pound-feet of torque that the Prius
transaxle by itself to the tires delivers does not include torque from the engine so the engine will
add another the engine has another 105 pound-feet of torque that they can deliver to the counter
driven gear that still would go through torque multiplication so the Prius version not the
Prius prime would end up with more to the ground torque than the Prius prime would so that's why
they had to go with the higher numerical gear ratio on the Prius Prime in the final drive is to
make it accelerate the same way that the Prius the regular Prius would with the internal combustion
engine and that's still a little bit lower but it's good enough that people are happy with it. all
right the next thing to see here on the transaxle is we have three gears left. this gear over
here is the equivalent of the ring gear of the power split device on the previous transaxles
the hybrid transaxles these two gears over here this small gear right here is driven by MG2 and
it has 17 teeth on the drive gear and 53 teeth on the counter driven gear which gives us a 3.118:1
gear reduction from MG2 to the counter driven gear which turns the final
drive pinion gear so what I'm telling you is these two gears right here are the equivalent of the
motor speed reduction gear set that was in the P410 the P5 10 the P310 can and all those other P3
series transaxles in a planetary gear set style so we've got rid of a planetary gear set and all it
was doing was giving us gear reduction this gives us gear reduction also but MG2 comes in on this
side of the counter driven gear to give torque to the final drive gear that sets right here to
propel the vehicle down the road so that's MG2s contribution, but now the internal combustion
engine, which remember this is the input shaft this is where our torque limiting clutch disc
splines and connects from the engine and turns at engine speed so we have the engine over here
on the other side that turns one of three pieces of the power split device planetary gearset, we'll
look at those here in a moment but it's still the planet carrier just like in every previous Prius
transaxle design and then MG1 the electric motor down below in the case here turns the Sun gear and
then the ring gear is just simply inside of this housing so this is very much like the big counter
drive gear from the P410, P510, and the P310 series transaxles we've got the counter drive gear on the
outside we have on this one a single internal gear or ring gear for our planet carrier to rotate
inside of so, that's our engine rotating that it sits on to great big bearings that sit inside of
the transmission housing right here and then our counter drive gear is just right here you can
see we have tapered roller bearings that need to be preloaded with the shims that we talked
about before and then our last gear right here is connected to MG2 so this is MG2 spinning down
in the case this over here is mg 1 spinning down in the case MG1 MG2 they both can contribute
torque to the counter driven gear and the final final drive. all right now this transaxle uses some
sealed not really sealed but it uses bearings that have o-rings on the outside of them. and that
forces any lubricant to go through the bearing the ball bearing these ball bearings rather than sneak
out around the outside of the bearing cup now where have we seen that before first generation
Prius at the same design except it was just a single ring rather than a dual o-ring we've
got a sealed boring style bearing on the inside of this drive sprocket support, there's a sealed
bearing right there with the o-ring we've got it on both sides of this drive gear for MG2 and
those o-rings make it a little tight to get get the assembly out of the case because they're
they're squished in there make sure that you lubricate those very well before you put this
back in otherwise you'll cut them but this is the drive gear that MG2 rotates as you can see it
has splines right here that are going to connect to the MG2 rotor, it has a seal right here of some
sort I don't know if it's a lubricant or cooling lubricant seal or something for NVH reduction I'm
not sure, I've never seen something like that in the previous transaxle ok over here the Sun gear
that mg one rotates actually is splined onto MG1 along with a bearing race down in the case so
we've got a Sun gear that splines onto the end of MG1 rotor when we get that out here in a few
minutes, okay you can see right here in the case we have an oil pump pickup tube and screen assembly
so I'm going to remove that it has an o-ring that slides right into the oil pump in on the back
cover of this transaxle alright then we've got the park linkage in the rest of the parking pawl
and the detent over here we'll take those out a little bit later we have a cooling pipe right here
so our banjo bolt and that holds from the heat exchanger come in right here goes into this pipe
comes up and cools mg two's stator it goes through the case here and cools mg ones stator as well and
you can see just like we talked about on the other case half the final drive will be spinning,
it will be spinning in this direction, that's the front of the vehicle the final drive turns
the same speed and direction as the tire so it flings oil up into these oil cats tanks where it
drips down through different holes to lubricate bearings and so on what they're trying to do here
is reduce the use of an oil pump and use this oil slinging method to get as much lubrication
and cooling done as possible to try to be more efficient especially on the Prius Prime the
plug-in Prius it actually has an external electric oil pump that will come on as necessary to provide
cooling and lubricant all right let's take off the three-phase cables and connections right here
on the side of the transmission so you can see all six three-phase cables right there and how little
tiny they are this system only runs on 600 volts maximum rather than the 650 that the previous
third-generation Prius ran on these cables are of course extremely short so there's lower voltage
drop lower power loss they connect I already showed you directly to the inverter converter
that sits on top here and then they have this same type of connection where it bolts into the
transaxle and three-phase cable connections to the stators right below it so we have a protective
shield that comes off first that protects the plastic components I believe from heat and any
type of physical damage then we have a weather seal that goes across the top here this weather
seal you got to be real careful with it has a clip of course it's plastic so it'll break if you
look at it wrong undo both sides very carefully here we go so there's our weather seal once again keep all this stuff separated these
electrical connectors and connections need to be clean and dry and now you can see the
six bolts that hold the three-phase cables to the pass-through connector right here in
the case break all those loose and get them out of there all right so now the three
this whole connection can come off just like that the rest of this stays on for a few
more minutes we cannot remove it because it is physically connected with some bolts to the
mg one state or an mg to stator down inside the transaxle get this stuff out of the way
we also have a pass-through connector here for both temperature sensors that are in the
transaxle one through each stator and that's part of this pass-through connector we also have
the transmission vent right up here on the top of the transaxle okay before we turn this over in
and work on the other side of this transaxle the Toyota service information typically tells us to
use some blocks of wood to lay the transaxle on so that we're not denting any pipes or park
linkage or springs or anything else here on the side of the case my experience with blocks
of wood is they like to slide out of place and leave splinters of wood where they shouldn't and
so I figured out to put some just put some of the case half bolts back in it and let them
extend up high enough that it's not going to interfere or allow any rubbing to take place
on any parts that are they can be damaged so just stick a few bolts in there okay just like
that all right so we're ready to turn this case over and work on the other side the heavy
part of the case is in the top because if the motors and the stators are in the top
of the case so I'm going to very carefully tip it up and around and back down I forgot to remove the oil pump drive shaft so
it just fell out I'll show you where that goes here in a moment but it is driven off of
the planetary carrier on the power split device off of the engine just like all
the other transaxles alright we've got a lot of bolts going around to hold this side
cover on the transmission case to remove one of the bolts, we have to remove one of the
cooler fitting lines here fitting adapter lines it just has an o-ring that does the
sealing of the threads so we'll take that out set it off to the side here for a moment
now we'll come in and remove these these bolts twenty-one bolts they all had just no they
didn't have any Loctite any threadlock on them it was just a little bit of the FIPG
on the tip of them that was there. all right the side cover of course is held on with the
same the Toyota FIPG material there should be some pry points here's one right here it's
quite obvious there's another one right here there's one right here there's
another one right here another one right there they're all over the
place if you look for them just keep that falling out once again be careful you don't pry somewhere
you don't, or where you shouldn't that might cause some damage to the ceiling surface and pry
on the alignment dowel area, they typically do not put sealant on the outside edge of the alignment
dowels so you're safe to pry in that area there's another alignment dowel right here. now we've got
stator windings just inside here so you don't want to be sticking a pry bar deep inside and trying
to pry on whatever you can find there we go okay so we've got our side cover right here just here
on the inside of the side cover we have the MG2 resolver assembly the measures the rotational
speed direction and position of the MG2 rotor we have the MG1 resolver same thing on it. the MG1
resolver end and resolve a rotor that goes with is a high-resolution one on this model I'll show you
that here in a moment here's our oil pump assembly on the inside of this case now and then our pickup
tube for our oil screen went in right there we've got a temperature sensor coming in right here
and then an electrical connector right out here for both resolvers and the temperature sensor for
the fluid so that means we have three temperature sensors in this transaxle the fluid temperature
here for the output to the cooler and then we have two temperature sensors two more one for each
stator assembly all right we'll come back to the side cover here in a few minutes let's look at
the case as you can see here in the center case area with the side cover removed we have the
MG1 rotor and the MG2 rotor. now neither of these will rotate at this time because they're a
they're full of very strong magnets and they're sticking to the stator assembly because we remove
them the supports by removing that side cover that hold them centered inside of the stator so don't
try to rotate them and don't think something's wrong with them if they won't rotate you've
got to take them out as an assembly if you're going to change one we have MG1 temperature
sensor right here MG2 temperature sensor an electrical connector right there we have just
a beautiful mg two stator assembly here Toyota calls that a segmented winding we're segments
of a special conductive copper alloy are welded together rather than little tiny windings of wire
in one continuous loop like on the previous stator assemblies all right so to get to remove these
rotors and stators assemblies like I said we've got to take them out as an assembly I've seen
videos on YouTube of other people disassembling hybrid transaxles and they're in here big pry bars
pry in on that the resolver rotor and smashing the windings of the stator you don't need to do that
you let gravity do the work for you all you do is loosen the bolts and turn it over and lift the
case off of them and they'll come right out all right so I'm going to tip this up on its side
and take the bolts out and then take the stators out myself just sitting right here you
can see here in the back of the case we've got the six bolts that bolt the stator windings with
three wires each to the pass-through connector on the top of the transaxle before we remove
the stator assemblies we've got to unbolt them from the pass-through connector and of course
we need to undo the temperature sensors and get them out of the way also so we've got the mg two
temperature sensor right here it just done plugs just like that the mg one temperature sensor
is right here it bolts to the case and sticks inside of the mg one stator just like that
there's a hole right there where the temperature sensor plugs into so the temperature sensor right
here just plugs into that hole to measure the temperature of the stator now there's this little
rubber piece right here that falls off and if you didn't notice it and it falls off and you lose
it you'll, be in trouble. that plugs on right to the end of this drip tube right here and I'll
show you that in more detail here in a moment but when you take this side cover off chances
are a little rubber plug is going to not plug but this little rubber piece is going to fall
off and you will lose it so hang on to that there's an electrical connection right up here
for the pass-through of the temperature sensor just like that and then this electrical
connector right here just has a slide off clip that holds it to the little drip tube for
the mg one cooling put the little rubber plug in the bag here with this with the rest of
this stuff here from the stators I'm going to undo all six bolts here next you should
not use an impact gun on stator connections a little pass-through pieces are plastic they
harden up over time and they will break if you use any type of an impact on them so be
careful just using a little hand ranch or little socket quarter-inch drive what I
use on these things take them off by hand those all on the same bag now I need to show you
the resolver rotors so remember the resolvers that I showed you in that in the side case track the
speed position and direction of rotation of the rotors themselves but what's happened here on this
new design P610 transaxle notice the rotor has five cam lobes on it now instead of the two that
we used to have it has five which I believe gives a better resolution now if we look over at the mg
two rotor right there it only has the regular two but it's always had so I do not know why one has
two of them and the other one has five maybe they need the five-lobe one for the Prius prime version
where they use MG1 to help propel the vehicle also, I just don't know I haven't been able to
find anything describing that in the service information or any SAE documents or patents I
haven't found it yet I'm sure it's there I've just missed it so if any of you know put a
comment in the box below there and let me know alright so we are ready to remove these stators
they have three only three bolts each let's take this upper one out first like I say I've had this
apart before I did not retorque all these bolts if you do any work on aluminum house transmissions
you'll find that over time you can only torque bolts so many times before those aluminum threads
give out so we are I'm going to wait until I have to put this back together because this trans
axle actually has to work it's got to go back in vehicle I took this out of a brand-new 2017 Prius
eco it's over here on my hoist I took it out just to do this video I wanted to see what the new
transaxle design was and if it was the same as the Ford ones have passed and so on and like
I said it's similar to the Ford ones of the past and also similar to the new Chrysler Pacifica
van hybrid van plug-in hybrid van transaxle but there are some differences too alright let's
remove the stator and rotor assembly the rotor assembly is still in the bearing that holds it
in place on the other side that keeps it centered but there's the bearing that holds it in place on
this side is in the side cover and removed so the rotors kind of tilt it off to the side a little
bit and so to get the stator and rotor out as one assembly I'm going to have to come in on the back
of the transaxle here and just tap lightly on the backside of the rotor the MG1 rotor spline hub
right there and the MG2 spline hub is right down here so I'm not going to hit it really hard I'm
using a rubber hammer I'm just going to tap like that I felt it come loose so we'll go back
to the other side and this whole assembly now can lift right out now whenever you take a
stator assembly out of the transaxle like this you need to lay it on the stator frame
do not lay it down sideways where you could damage the stator windings or this resin type
material that helps keep this data windings cool you can see the rotor is inside of that
I'll show you how to how I get that out here in just a few minutes but let's get the MG2
stator out next so I'm going to come in on the backside with my rubber hammer and just
knock it out of the bearing just a little bit oh I guess I would help to take the three three
stator both gone but why is that not coming while we're here right here is a stator drip pipe for
cooling that will take out before we remove the stator here on the MG2 so this tube right here
drips fluid down onto the stator windings it's fed fluid from the oil pump after it's gone
through that heat exchanger and then through that long pipe I showed you into here and then
there's little holes in here where it just drips down onto the MG2 stator this by the way is the
prettiest stator I've ever seen the color of the wiring, just a winding of the stator itself
is just a beautiful stator makes me wonder if the rest of them look that way when they're brand new
and then they just oxidize over time okay so we're ready to take out mg MG2 stator now that we've
got the bolts undone let me finish tapping the MG1 wrote or MG2 rotor out of the bearing alright
you need just a little bit more assistance from the other side I'm going to come in with a brass
drift and just tap my hammer can't get to the my rubber hammer can't get to the surface I need
to tap on so I'll just tap here we go with this breast drift now it's free you can see the entire
stator assembly is starting to move forwards so we'll just slide it forward keep going upward lift
on it so we don't damage any of the laminations and there we go so here's our MG2 rotor and
stator assembly and the three wires that go to our pass-through connector so let me set that out
of the way for a moment now left what's left here in the case is another drip tube just like that
other one I showed you and remember that those drip tubes get fed by the fluid coming from the
heat exchanger through this pipe and through to this plastic one I already showed you the drip
tube for MG2 and through the case on the other side for MG1 for cooling so I need to next before
I can get that drip tube off I need to remove the, I need to remove the three-phase pass-through
connector and here comes the whole pass-through connector assembly right there and then the very
last piece to remove on this side is our drip tube that provides cooling for MG1 so right there all right so we've got everything
on this case disassembled except the vent I'm not going to take that out and this transfer pipe
right here I could take it out but, there's no there's no reason to take it out at this point
if I was overhauling this transmission I would certainly take that out and clean it and I would
disassemble the parking linkage and make sure that it's not worn out and clean that too but it's
the same parking linkage as every other Prius transaxle up to this point the same component
so I'm not gonna I'm not going to take that out either all right so we are done with the center
case so let me get that out of the way okay the next step is to remove the rotors from the
stators why well just because I want to take a look at it these rotors have been updated
since the previous Prius transaxle the p4 10 and I want to show you there can how they've
been updated in their configuration and look at the power ratings and torque ratings and and
so on so to get those out because they are held in place quite tightly with permanent magnets
I use some sort of a foam pad so this is just a snap-on kneeling pad to kneel down if you're
working under the dash of a car and you're your knees are on concrete I'm going to use that as
a pad to catch the stator assembly when I push it when I push it out now the stator assembly has
the resolver rotor side and we do not want to push on that side and that has the other side with
the splines that hook to the Sun gear and has a big knot here and I'm going to use that
side what I do to remove the rotor is I just get a big socket and I don't use the socket to
undo anything here I just use it as a pedestal I just use it as a pedestal to lift up the whole
assembly just like this and then I'll just come in and push down just like that and there's our
there's our rotor and I put some labels on it I wasn't sure if they would clear the stator
with it installed but apparently they did so it's got a little bit of an air gap
there but you see I did not do anything to damage the rotor is the MG1 rotor I'm just going to
set it right over here for the moment the stator itself when it came down it landed on this foam
pad which didn't damage anything and so now when I set it back on the hard table it I'll set it
on its stator frame with the three-phase cables sticking up so that it won't roll over and damage
them and then we'll do the same thing here on the MG2 rotor and stator assembly on a deeper one
like this sometimes I have to use an extension to lift it up higher just the way to assembly
almost takes the rotor out by itself on this this model some of the previous ones had much
stronger magnets in the rotor but this one's fairly weak relatively speaking so now I'm just
going to push down just like that and that's all I've done on the other ones it just it took me
and another person to do it I don't have that much strength when you guys could probably
do it yourself pushing down but if you don't have something soft for it to land on there your
chances are you're going to damage the windings as we talked about so here's our MG2 rotor and
I'm going to set it away from MG1 and away from anything magnetic because everything will stick
to it and it will it could possibly damage the state possibly damage the rotor also so now tip
this back up and set it over here out of the way so that's our stator isn't that beautiful right
there that's that is a pretty stator you can see where the segments were welded over here rather
than a continuous winding like the small wire small round copper wire stayed here skaters in
the past as a matter of fact one of the things that they're bragging about on this transaxle
is they use less copper they use less permanent magnets to use rare earth materials to make
the rotors themselves so a more lightweight more efficient design alright our next step is to
disassemble this side cover with the oil pump and the resolvers now these resolvers have a dowel pin
in them that dowel pin right there that dowel pin aligns the resolver with the case and you cannot
get it out of adjustment as long as you're paying attention there you really could put it in several
different actually three different orientations if you're not paying attention but there's there's
a black plastic tab right there that should point at the alignment dowel now each of these resolvers
is marked differently it's a different part number this one right here actually says mg two right on
the top of it this one of course says mg 1 because that's what they're for ok we have
a wire harness right here that goes through to a external connector I'm going to take the bolt
out of the external connector the bolt that holds the temperature sensor and the wire harness
bracket in place and get those out of there this bracket keeps the wire harness away from
all the rotating parts and the hot part and then the electrical connector just unplugs
out of each resolver the temperature sensor on plugs and sticks out the side of the side
case here where it has a little connector that unplugs also so then we've got the wire harness
and the electrical connector that goes with it I'll just took those two back together and it
will bag all that up get it out of the way okay next, we've got the two resolvers they're bolts
are the same but the resolvers are different because of the positions that they fit in so
if you look at the resolvers here you'll see there's a dark plastic tab the points right
here on the MG1 resolver and that plastic tab points over here on the MG2 resolver those
tabs point to the location where the dowel pin here's a dowel pin and here's a dowel pin
should line up now if I take the MG2 resolver I can take it out of alignment like that it's
almost not quite a hundred and eighty degrees out of alignment but of course the wire harness
would not plug into it so that'd that would be difficult but that's the right way and now
it's I guess it's it only goes on the one way if you want the wire harness to plug in
so that's somebody was thinking there. with the past transaxles and how all that could get
messed up if somebody accidentally took those resolver bolts out all right the last part that's
in the in the case here is the oil pump assembly so it has several bolts that hold it to
the side cover looks like nine bolts and then this pump has some alignment dowels
that hold it in alignment with the side cover itself and so it's not going to
just fall off or come off easily on the case here or the side case so there's a
couple of price points there's a dowel pin here and a dowel pin here we got to come
in and lift up at the prior point around the prior point areas without damaging the
surface that it just about there we go okay so here's our oil pump assembly you can
see the troll COI pump gears in the back here and then of course you can see some of the
case passages here in the front now if this was the Prius Prime plug-in Prius it would
have some additional fittings out here on the side case for the electric oil pump that
is used when the internal combustion engine is not being used while you're in EV mode now
this oil pump comes apart even further and it has some little spring-loaded pressure
regulator valves inside of it two of them one of them is the standard overpressure
valve that all Prius transaxles have where if the fluid pressure gets too high this
valve will open up and just dump the excessive pressurized fluid into this into the case
the other valve that's new to this one and there's a plate here I'm taking off I've got to
hold down against the spring pressure of these two valves when I take this bolt out the other
spring-loaded valve is a cooler bypass valve so if the cooler that heat exchanger on the front
of the transaxle we took off if that were to get restricted or plugged or any of the pipes it'd
get plugged like that then this second valve would open up and allow the fluid to go to the bottom
of the case inside the transaxle and just bypass the cooler at that point now if that happened
then eventually the transaxle could overheat and it would trigger a trouble code and maybe a master
warning light and so on now on these two valves the valves themselves look identical these are the
two spring-loaded valves I was telling you about this is the pressure relief valve if the oil pump
pressure gets too high this is the cooler bypass valve if we lift those two valves up there Springs
underneath them notice this one is painted white and this one is not painted the one that's painted
white has a lower spring rate than the one that's not painted in other words the cooler bypass valve
will open before the overpressure valve will open and that makes sense so we've got those
two springs and then the last part here is the crocoite pump itself and I want to show you I want
to show you how big this pump is the pump gears they're huge so let me set this here on that on
the bench there's the Trochoid pump out of this P610 transaxle now let me grab the other two
toroid troll koi ponds one from the P510 one from the P410 so here is the P510Trochoid pump
which is in the Prius C, and here is 1st 2nd and 3rd generation Prius oil pumps right there so
they all have the same diameter but obviously there are different thicknesses the different pump
thicknesses will result in a different volume of fluid being moved and this one for the p610 is
not quite twice as thick as the one for the P510 but it's close to twice as thick which means
we're moving a lot of fluid in this transaxle and I'm sure that's for keeping those stators cool
because I obviously besides the lubrication but keeping the stators cooler and the rotors cool
is an important thing alright so that is the oil pump assembly all by the way there's some
dimples or dots on the gears here those go down in the housing there's a lip that has a recessed
bore on the inside pump gear here that if you don't get that lined up it won't fit in place
alright so we'll get our oil pump assembly out of the way all right we're ready to put put
all the gears into the bell housing portion of the case where we can see everything interact
together with both the MG2 and the MG1 rotors and everything else so the first thing that
needs to go in here is the power split device planetary gearset which in this big housing here
contains the planet carrier that hooks to our clutch damper assembly now for this demonstration
I'm going to remove the planet carrier from this counter drive gear assembly so that we can have
the two pieces together separately to do that I need to remove one of these bearings so let me
press that out real quick ok so I pressed out the bearing that's on the parking gear side of
this counter drive gear housing and now you can see down inside here is the internal gear or
ring gear of the planet carrier for the power split device the planet carrier connects to
the engine through the clutch damper assembly so that is just like the P410 just like the P112
just like the P111 just like the P510 all of the others, the power split devices have not
changed in all 20 years of the Prius transaxle operation it's they all have the exact same
number of gear teeth they all have the exact same gear ratio on the power split device okay
so on this front bearing here there is an o-ring that if I don't remove that o-ring it will
fight me putting this on and since I need this all ring to seal when I go back
together for real I'm going to take that out and keep it in good shape off to
the side here so now the counter drive gear that has 65 teeth will slide into the
bell housing side of the transmission case it's a tight fit it's not a press
fit but it is a tight fit there we go those tight fits they always fight you
but don't hit down on it or you'll run a pretty good chance of causing bearing
Brinnelling all right so this is the ring gear of our power split device here's
our planet carrier that connects to the clutch damper assembly there is a
bearing that goes on here and a spacer and then it just lines up with the planet lines up to Planet gears with the internal
ring gear so the internal ring gear and the external counter drive gear are that in the
same housing they turn at the same speed but they have different number of gear teeth
all right the next thing that would go on to our power split device as in any other
Toyota Prius transaxle is the Sun gear so we've got the Sun gear of our planetary gearset
so any planetary gear set has three components the Sun gear which connects to our mg one motor
generator starts the engine gen and also generates power to recharge the battery and to send power
to MG2 we've got the planet carrier that I just installed that hooks to the internal combustion
engine or ice and then we have the internal gear the ring gear here that is connected to the same
housing as our counter drive gear so I'm going to put and it has a bearing on it the Sun gear down
into the planet carrier and then I'm going to take our MG1 rotor and line it up and set it down
into the Sun gear just like that and then our oil pump drive shaft that turns that great big
high volume pump goes down through the middle of that and connects to the planet carrier and
so this drive shaft will turn the same speed as the internal combustion engine alright so here
is our MG1 rotor the MG1 rotor is rated at 23 kilowatt which is 31 horsepower,
it also has 40 Newton meters of torque or 30 foot-pound of torque maximum and that is used
we only use that torque on the Prius prime when we use MG1 to help propel the vehicle under
certain conditions alright the next thing that we install is the MG2 drive gear the MG2
drive gear here the MG2 drive gear of course has MG2 stater connect to it now remember this
these have the ball bearings and the spacers that position it in the case and probably preload
the bearings too but this one has the o-rings on it so we need to take the o-ring off for
this demonstration so that I don't ruin it so it has to brown colored or rings the reason
I'm taking those off for this demonstration is they interfere with putting the gear and
varying assembly down into the case for this demonstration so we've got our spacer I'm sure
that is a selective spacer and then our mg to drive mg to driven gear the MG2 drives it goes
down in the case next and of course MG2 then comes along and splines into the top of it and
MG2 is rated at 53 kilowatt 71 horsepower 163 Newton meters of torque which is the same as 120
foot-pound of torque and both of these motors have less power of in the motor themselves than
any of the previous Priuses out there but what we do to get more torque out of them is to use
gear reduction any time you go through a gear reduction you also get a torque multiplication
and so we end up having more torque as I lightly explained earlier by going through gear reduction
than any of the previous Prius transaxles okay the next part that goes in is our counter driven
gear the counter driven gear has teeth on it right here that will spline to the mg to driven
gear and also to the MG1 power split device counter drive gear so there's this what I'm
saying is this gear receives torque from two different locations MG2 gives it torque MG1
in combination with the internal combustion engine gives a torque on the regular Priuses and
then the Prius prime Prius plug-in MG1 itself can add additional torque without the internal
combustion engine so we will set that in here next just like that so now we can see on the previous
all the previous Prius transaxles anytime you rotated MG2, it always rotated the ring gear or
internal gear right here of the power split device and notice now I'll hold MG1 from rotating if I
turn MG2 this ring gear rotates so it's exactly like the previous transaxles but it's just
accomplished differently through this parallel axis transaxle design rather than the in-line
axis where we had MG2 over here on top of MG1 with another motor speed reduction planetary
gearset in between them well the motor speed reduction planetary gearset is out but we still
have motor speed reduction going on through the counter driven gear the MG2 drive gear and
the counter drive gearing over here and then of course, our last piece to come in is our final
drive assembly just like that so on all previous Toyota transaxles if MG2 rotated at all so did
the final drive which connects to your CV half shafts which connect your hub and bearing assembly
and your wheels and your tires they all turn the same speed as this but we've got a huge gear
reduction going on. now here in the P610 so in order to move the vehicle forward one rotation
of the tire if you have the Prius it's going to take 10.838 rotations of MG2
to get one rotation of the tire and it's going to take 12.3 rotations of MG2 on the
Prius prime Prius plug-in to get one rotation of the tire now how does that compare to previous
just the previous model the P410 the P410 was 8.6 rotations. the P410 was only
8.6 revolutions but the P410 had higher horsepower the higher torque it had 60
kilowatts instead of the 53 that we have here and so it could handle a lower numerical gear
ratio and still accelerate well now since we've gone to lighter weight smaller rotors for both
MG1 and MG2, they need to spin at a higher rpm to have the torque and horsepower that they need
and so they have stepped up the rotate maximum rotational speed of both of these gears or
both of these rotors to 17,000 rpm which is incredible the P410 was at 13,500 the P112
in the second-generation Prius was at 10,000 and then the first-generation Prius was at 6500.
but what they've done over the years since the first generation Prius is that while the first
generation Prius had a huge rotor with a lot of torque it was 259 pound-feet of torque
I believe and we've only got 120 here but it had a gear ratio that wasn't very good it
was turning like four-point we find it here now the first generation Prius took 3.9
revolutions of MG2 to get one rotation of the tire and then the second generation
one up to 4.1 and then the third generation went to 8.615
and now we record up to 10.8 for the Prius and 12.3 for the
Prius Prime and Prius plug-in so faster and faster rotor speeds less power of the rotors
themselves but through the gear reduction in torque multiplication we actually end up with
more torque at the wheels than we've had in any of the previous designs so high speed
rotors I want to show you something they've done with the rotors they Toyota published in
the SAE Society of Automotive Engineers a paper called development of a new hybrid transaxle for
compact class vehicles and in this document it tells us several things about this this transaxle
about how they've reduced its weight and it's a new parallel design it's 47 millimeters less
in width, it's weight has been reduced by 20% they used less rare earth materials and magnets
the volume of magnet used was reduced by 15% compared to the P410 they used segmented
windings in the rotors are in the stators which reduced their weight by 21% they help reduce
copper loss also and then about the rotors themselves and I call here from the document a new
high-speed low loss rotor was developed to support the high-speed rotor a lock nut method was adopted
to tighten the core so if we look at the bottom of these rotors, you can see a great big nut here
on the back of them, we didn't have the great big nut there before that's something that the Ford
transaxles used and then with that not tightening the core of all these laminations there's also
no great big thick clamping plate on the top of the bottom we are just right to the laminations
themselves and if you look closely you can see the little V grooves that the magnets here's a
V right there the V-shaped magnets to give it 50% more strength than the flat first generation
Prius design rotor so it's a more powerful rotary it goes on in this document and I quote
furthermore, a magnetic circuit design was developed that improved the reluctance torque of
the rotor core this improvement was made possible by motor size reduction achieved through measures
such as increased rotational speed as a result the volume of magnet used was reduced by 15 percent
compared to the P410 now an interesting thing an interesting thing on the MG2 rotor now before
I show you this the first generation Prius MG2 rotor just used the flat bar magnets in aligned
around the outside of the rotor there the second generation Prius went to the V configuration
magnets and if you're not sure what I'm talking about the go look at the P112 deep-dive video
that I made it I'll show you it actually shows you this the configuration there well the third
generation Prius continued that V shape but this fourth-generation one looks different even from
that now I found nothing in publications to prove this but let me show you what I'm talking about
here so if you look at the little notches these little notches in the top cover here of the rotor
you'll see like right here there's one in the one pointing in this angle that's a magnet there's
another one pointing at this angle that's a magnet so there's the V configuration right there like
we've had since the second-generation Prius but there's also a flat bar magnet that goes across
this way there are three magnets there from what I can tell I can run my screwdriver across it
and I can feel the pole I already change across those three magnets and then there's these two
little what appear to be little tiny magnets in the back there so it almost looks like there's
five magnets unless those two in the back or just continuations of the two that are v-shaped
anyway so at a bare minimum there's at least three magnets in this rotor shape if any of you
know what what the configuration is there I don't know why I like to know stuff like that but it's I
think it's cool to find out the inner workings of of these things okay so we've got all of the
components here now let's just go through the power flow see how this thing transfers power
in in the different modes and we will be done with this amazing P610 transaxle okay so as
you're driving down the road in electric vehicle mode with the engine off the planet carrier the
internal combustion engine is off and there's a gear ratio from MG2 to MG1 of 1.199 or 1.2:1
which means MG2 will spin 1.2 turns for every one turn of MG1 which is kind of unusual
because in the past MG1 has usually spun faster than MG2 but in this case, it's not so let me
hold the input shaft rotating I will turn MG2 1 and a little bit more 1.2 turns 1 on the 4th turns
approximately to get 1 rotation of MG1 all right that keeps MG1 from over-revving even though
we have a maximum speed of 17,000 rpm so that means that MG2 through the tower driven gear is
driving the final drive it's also turning MG1 and having it either generate power or just kind of
sit there in a low-power mode almost totally off I know it says off but it's got to be generating
just a tiny bit of power you can't spin a magnet inside a coil of wire without producing some some
voltage so so in electric vehicle mode now if we want motor-generator one like on the Prius prime
Prius plug-in to help MG2 through the counter driven gear propel the vehicle with the final
drive gear here we need to power up mg one and have it rotate in this direction but you'll notice
if I turn mg one in this direction the ring gear is not moving there's no power being transferred
and let me remove the mg one so you can see what's going on here I'll zoom in okay so this Sun gear
right here is connected to mg one so if I rotate this Sun gear that's the same as turning the
mg one rotor so notice as I turn this Sun gear the planet carrier right below it is spinning now that planet carrier connects to the clutch
damper flywheel and the engine crankshaft well that just happens to be in the opposite direction
that's a reverse rotation of the engine well we don't want that to happen because that doesn't
allow any torque to be transferred to the final drive ring gear we want mg one to help mg to
propel the vehicle down the road so if we could stop the planet carrier from rotating so now
I'm going to hold it with my finger and keep it from rotating I'm still going to turn the Sun gear
notice now everything rotates and we are supplying power to the final drive through the MG1 rotor
so we have to stop the planetary carrier we have which is hooked to our flywheel and clutch damper
assembly and that's why the Prius prime has this one-way sprag clutch assembly this one-way sprag
clutch assembly has some spring-loaded sprags that at the higher speeds they will fling out and
not be dragging like a ratchet would as you as you rotate a ratchet here that ratcheting noise is
little Spragg teeth inside that are spring-loaded clicking on some little teeth but if we turn it in
the opposite direction then it locks up if we were to hold the shaft or the socket from turning
we can't turn the ratchet that's the same idea as we're using with the flywheel and one way Spragg
so as we start spinning mg one in the direction we want it to spin to help propel the vehicle that
will cause the flywheel to change directions and as it changes directions, it will stop spinning in the
one direction it has to come to a complete stop and then start spinning the other direction
at that one point where it stops to change the directions is where those spring-loaded sprag
teeth will come down and engage and lock it into into place and then the mg one can help propel
the vehicle down the road it's a neat system now that is not unique to Toyota if we go clear
back to the 2005 Ford Escape it has a one-way sprag on its planet carrier the 2017 Chrysler
Pacifica minivan with the SI -eVT transaxle has a one-way sprag on its input planet carrier so all
three the Ford design the Chrysler design the Toyota design have used this sprag method now
interestingly enough the lighter model affords the second third-generation Ford transaxles got
rid of that and I'm not sure it was really used in the first generation one but it's there I'll
show you a picture here on my first generation Ford hybrid transaxle over there now like on any
of the previous hybrid transaxles that went in the Prius or any other Toyota hybrid we can contribute
up to 100% of the engine torque to help mg to propel the vehicle down the road now how is that
accomplished it's accomplished through the power split device planetary gearset so we've got three
pieces of the planetary gear set we've got mg one that turns the Sun gear of the planetary gearset
we've got the engine that turns the planet carrier and then we have the internal gear or ring gear
that is connected to MG2 and to the final drive and so a neat thing about planetary gear sets
is if you force any two of the three components it doesn't matter which two if you force any of
those two components to turn the same speed all three pieces will turn the same speed which means
there is a engine rpm for a specific vehicle speed where the MG1 rotor speed which is the Sun gear
will match the engine rpm that drives the planet carrier now I did some math for this vehicle
here the 2017 prius with the P610 transaxle if you're driving 65 miles an hour down the road you
will get 100% engine torque with an engine rpm of 3,240 so at engine rpm at 30 to 40 the MG1 rotor
speed is also 30 to 40 so that's the carrier and the sun spinning the same speed which locks
all three pieces together here on the power split device and all of the engine torque can be
transferred into the final drive helping mg to propel the vehicle down the road now there's
also another speed engine rpm where MG1 totally stops and that is if you're doing the
same 65 miles an hour it's just 900 rpm lower at two thousand three hundred and forty rpm so
at two thousand three hundred and forty engine rpm that's spinning the planet carrier 23:40 the
rain gear the internal gear will be spinning in the opposite direction and at that same time
MG1 just sits there we're not electrically stopping it from rotating it's just that that's
how it works out with the planetary gear set so kind of interesting if it's totally stopped
obviously it's not generating any power and that might be useful if your battery is full and
you don't need additional power to help MG2 drive the vehicle down the road you just simply
turn off the generator by quit having it rotate and then we can we can speed it up or slow it
down faster than engine rpm or slower than engine rpm just by changing the engine rpm so we can run
it up to its maximum rpm positive or negative to generate current no matter if we're in a positive
or negative torque as situation very interesting a very neat design and like I said every Prius
every Toyota hybrid transaxle uses that same power split device to act as a continuously
variable transmission in regard to the engine rpm Toyota calls is an eCVT, an electronic continuously
variable transmission so MG2 has nothing to do with being continuously variable it's a traction
motor that is directly geared to the final drive if you turn MG2 you're going to move the vehicle
down the road but the continuously variable portion or infinitely variable if you want to call
it that is the speed of MG1 versus the engine alright well I've had a good time disassembling
this transaction and getting to know it it's definitely different than what we're used to
as as far as Toyota transaxles but I get the feeling we'll see bigger versions of this neat
transaxle in the future, thank you for watching
Anyone who watches this will suddenly understand why transmissions are so damn expensive. They’re mechanical works of art, mass produced.
The engineering wizardry is matched by this guy's complete knowledge of the transaxle. I found the engineers who designed it could disassemble and disassemble it like this.
I’m so happy there’s people like him that have the patience and experience for this kind of science. I don’t think I have the brain capacity to learn this stuff.