Basic torque converter operation

part four of this basic seven part series is going to cover torque converters and their use in an automatic transmission a torque converter is going to live between the engine and the transmission it's the component that delivers torque from the engine to the transmission it's filled with fluid and all that torque transfer is done primarily through a fluid coupling so there's no physical connection at least until the torque converter clutch applies more on that later but during basic operation there's no actual physical connection it's all done through fluid so that gets me to these three different purposes main purposes of a just a three element torque converter one which is a big one the ability to come to a stop or a stop light stop sign without the engine stalling on a manual transmission i gotta put my foot down on the clutch the disc can disengage the engine from the transmission on an automatic transmission not to do anything also we're gonna have this smooth uh transition of power when we go to accelerate since it's all done through fluid when i go to accelerate i usually get the engine to rev up and the vehicle to launch and everything's smooth there's no jerkiness involved and that can also happen during the shifts when i'm shifting from one gear to the next that fluid coupling can kind of dampen things out lastly we can multiply engine torque we're going to get more into this later because we take this torque converter completely apart and i describe all the pieces and parts and how it functions but basically this device right here which is a stator and allows for a redirection of energy in the torque converter and that allows for multiplication of torque that's a benefit that we have using torque converters and an automatic transmission but before we take this apart on the bench we want to get familiar with a few different things like some of the terminology here i've got an engine driven component we call it the impeller and that's in green then we got the transmission connected component that's the turbine and it's in pink and that blue item here is the stator that's the part that allows for redirection of fluid flow and gives us our torque multiplication down here i got a cutaway of the torque converter this is a honda 10 speed torque converter it's got a lot going on in it we'll actually see it i take it apart on the bench and we look at the parts and pieces involved in it too so those three purposes i told you about torque converter where you got multiply engine torque you got smooth acceleration transitions between shifts and the ability to let the engine to continue to run while i'm on a standstill or a stop this is another benefit of a modern torque converter since the 80s they've been putting lock-up torque converter clutches in and then becoming more and more advanced a lock-up converter actually uses a friction disc to lock up so you get a one-to-one ratio so what a lock-up converter is going to do for you is it's going to allow the engine to directly drive the input shaft of the transmission through the clutch so kind of bypasses that fluid coupling that we have in there why would we want to do that because that fluid coupling actually generates a lot of heat and that heat equates to energy loss and the energy loss is going to be poor fuel economy so by applying a lock-up converter clutch where we allow the engine to directly drive the transmission component we actually eliminate some of that loss so modern transmissions transmissions that have maybe five speeds or more six speeds or more they're gonna use they're gonna actively use this torque converter clutch you can use it many gears might come on as early as first gear and they're gonna do that to reduce the amount of energy that's lost during that fluid transfer phase that occurs in a torque converter let's take a look at how torque converters work with an automatic transmission there are a variety of designs and you'll see differences between them this one i've got a few different designs up here that i'll show you this is not a in-depth lecture on torque converters this is just a kind of a brief how does this thing work and what's its purpose in the transmission we'll look at more specifics on how they're controlled through hydraulics and so forth when we cover the transmissions in detail but this is a typical torque converter that we have right here this is actually off honda 10 speed when you pull a torque converter off the front of the transmission you just basically have this big vessel that you're looking at right here now on all these this one here is an allison and you can actually unbolt the halves on that this is allison 3000 4000 series transmission but with all automotive and light duty truck torque converters there's a weld that exists and you can't open this thing up unless you've cut it on a lathe like i did here and for that reason most time when people are rebuilding transmissions they put a new or remanufactured torque converter end torque converters are built and remanufactured by special facilities that do that there are some transmission shops that have the equipment that do it themselves but the vast majority of them order through their supplier remanufactured torque converters and you know these plants that remanufacture the torque converters they cut them open change the bearings change the friction material that's in there inspect everything clean everything a lot of times they replace this hub right here and weld the new one on and machine it they balance it so that whole process usually remand torque converters are 120 bucks or something like that so it's a pretty typical expected expenditure when you're rebuilding a transmission just to replace the torque converter because that is the one area out of all the stuff that we rebuild that the average shop cannot go in and inspect themselves so you don't want to take a chance of putting a bad part in to a fresh rebuild also if something fails in this unit anywhere in the transmission there's stuff that might get in here that you can't clean out so that's another reason why you usually just replace them and but let's see how they operate and that gives us an understanding of how this tran what they do in an automatic transmission so when you think about the purpose of a torque converter in its name it has torque converter in it so it actually does multiply engine torque that's a benefit that it has during that process of multiplying engine torque it creates a lot of heat and that's a drawback that it has another big reason why automatic transmissions have torque converters is because this is the device that allows us when we come to a stop that prevents the engine from stalling it's a disconnect if you will the torque you know during acceleration and torque multiplication the torque is transferred from the engine to the transmission through fluid so when you come to a stop and your engine idles down and your vehi your wheels stop turning and the input to the transmission stops turning well the there's no physical uh connection in the torque converter it's all done through fluid so it allows the engine to continue to rotate and while the input to the transmission stays still then when you accelerate the engines spins up faster and faster and the momentum of fluid that it throws actually drives the the transmission's input shaft that's what we're going to look at how it does that so i'm going to show you the internals now once again this is the vessel that you get normally it wouldn't be in two pieces usually it would be one solid vessel because that is a how the torque converter comes off let's take a close look at this torque converter as i mentioned before this was the honda 10 speed we're looking at the the torque converter the whole vessel and i did mention that this is normally welded together cut the weld out so we can see the insides of this looking at this side first you can see the center section is a hub this actually fits this whole assembly this hub allows me to center the torque converter into the transmission so there's a bushing that this will ride next to and and that will keep it all centered like it should be you might notice these cutouts right here these notches a sprocket on the inside of the transmission is going to notch to this hub and there's a chain that will allow the torque converter drop to drive an oil pump and that's where we get the pressure in our transmission from so whenever the engine's running this whole thing's spinning and we're spinning an oil pump through that chain and sprocket so that is a that's pretty much typical with all torque converters when we look at some of these other torque converters you'll see that they have some provision like this one's got flats machined on it right there and they have some provision to allow you to drive an oil pump sometimes there's a little mini shaft that fits in there but either way um yeah that's for the oil pump and if we flip it over here's a little weight by the way that's that's a weight for balancing that they put on there and this part right here is the pilot that allows you to center the torque vert into the back of the engine and the mounting pads for the flex plate this allows the flex plate to drive the torque converter and the flex plate's bolted to the uh to the um crankshaft to the engine so let's split this apart now realize that when the engine's running this whole thing's spinning right actually be going the other way because the front of the engine is on this side and this is the transmission side so it'd be counterclockwise from viewed from this side but from the front of the engine from underneath it would be clockwise so this whole vessel space so when i pull this apart the first thing you can see on the inside of this are these fins geez it's like a bell oh it's this side so when i open it up the first thing that we see are these fins right here remember that this is normally welded to the cover assembly so if the engine is rotating these fins are spinning with it regardless if we're moving down the road or not if the engine's spinning this is spinning and when you look at it they've got these this curvature to these little fins and the purpose of that is when the engine is running and it would be going in this direction the purpose of that is it's going to take the fluid that's in here centrifugal force when this rotates is going to want that fluid to kind of fling around the outside and the fluid that leaves this part is going to come over and contact the next part of our little assembly here which is the turbine this other set of kind of gold fins i'll put this off to the side right now this is called the stator we'll talk about that here in a second but uh yeah so this is the turbine and you're like well that doesn't really look that much different from the impeller and really the the idea is the same they've got these little fins but instead of the engine rotating and throwing fluid out of the impeller like it's doing the turbine is what receives the fluid so this is the transmission side the way i always remember is turbine and transmission um i'll start we'll start with t so this is uh the transmission's input shaft right here kind of just show you that like this is this is on the inside of the transmission this is the clutch assembly well and there's also a set of splines but this is the input to the uh transmission so when the fluid comes from the impeller when the engine is rotating the fluid comes from the impeller the turbine catches that fluid and it applies whatever force and torque from that fluid it applies it to the input shaft now okay so if this this is the transmission side and it receives the fluid from the impeller and then that fluid kind of comes back out well what we have next is the stator and that stator is going to be positioned right here in the middle and the purpose of the stator is to redirect energy the energy that has basically um so you think of the fluid energy that comes into the turbine that's the to a turbine blade it absorbs all that force but there's still momentum and there's still energy left coming out of this turbine and if i didn't have anything like a stator to redirect the fluid in the same direction as the impeller that it's spinning that fluid is going to actually push the impeller in the opposite direction you're going to actually lose torque so what they do is they put a stator assembly in there it's upside down put a stator assembly in there so the fluid that comes in to the turbine comes back out and then it bounces off the stator blade and ricochets back in the same direction that the impeller is spinning that allows us to multiply torque because we are basically recycling some of the energy you've probably grown up with a uh somebody or in your own house you had an above ground swimming pool right in the back maybe one of those 15 foot or 20 foot diameter swimming pools or like four foot deep well what's the most fun thing that you can do in one of those swimming pools you got it create a whirlpool so you get your buddies in there and you start marching around the outside of the circular pool and if you imagine you're getting this whirlpool you're getting this current getting all that water that's in that pool to start moving around and the faster you go the faster you go the faster you go the more current of fluid you've got moving around will eventually get to the point where you can just all that hard work paid off and you could just kick your feet up and you're just sitting there coasting around and floating and having a great old time drinking beer out of your koozie or whatever you do then of course there's always that one buddy that kind of falls in the middle gets stuck upside down and the whirlpool you gotta pull him out by his ankles but that's what's happening in a torque converter i'm using this momentum of fluid when that impeller is rotating it's taking that fluid and from my impeller tossing it to my turbine my turbine absorbs that fluid and then whenever energy is left over gets redirected off the stator back into the same direction that the impeller is rotating so i'm using the same force that i'm that i've created to drive the transmission to help the impeller spin that's the purpose of the stator it's fluid coming up from my impeller gets tossed over to my turbine my turbine absorbs it fluid that leaves the turbine bounces off a stator fin and goes right back into the same direction that the impeller is rotating torque multiplication that all works great as long as the impeller is spinning faster than the turbine say that i'm at a stop light and i go to accelerate well my engine revs up and my vehicle just starts to move so i might have an engine that's spinning 1500 rpm with an input to the transmission that's not really moving at all yet because i just started off from the stop light so at that point my impeller is spinning a lot faster than my turbine and during that mode there's a lot of this fluid that's coming from my impeller to the turbine bouncing off the stator redirecting it towards the impeller uh impeller turbine stator impeller turbine and you're doing these little loopy loop these little slinkies that's called vortex flow vortex is this little swirl that's happening a lot of heat created during that and there's also a lot of torque multiplication because i'm recycling a lot of that energy now let's take it to the other extreme now i'm going down the road after i've just accelerated from the stop light i got up to 50 60 miles an hour now i'm letting off on the throttle there's not that much speed difference now between the turbine and the impeller the engine and the transmission input shaft speed are going pretty close to the same speed so if my turbine is spinning fast along with the impeller the fluid that's left over and that comes with out of the kind of the bottom here or towards the middle of the turbine blade it doesn't want to hit this flat spot right there it ends up hitting the back of these stator blades and if i don't let this freewheel notice how it's got a one-way clutch in there if i don't let that freewheel it'll actually redirect in the opposite direction of the impeller rotation and that would slow the engine down that's what we call rotary flow or coupling phase so under acceleration it hits the front of the stator blade ricochets off in the same direction as impeller rotation but once i get up to coupling phase or you know cruising speed and the in the turbine and the impeller are going pretty close to the same speed the fluid wants to hit the back of the stator blade and it's allowed to push the stator out of the way the stator splines to this second set of splines right here these splines this is the input chest spline you can see i can move it this set of splines right here are the stator splines they're bolted to the transmission case so this part doesn't ever move you can actually see the little raised sections on the casting there that's where the bolts are coming in from the other side so the stator splines the stator will spline to that shaft that's permanent and it's mounted to the front of this transmission so to allow the freewheel in one direction and holding the other so that's how we're able to hold a stator looking at it in this direction this is the turbine side of the stator so when fluid is coming during torque multiplication when the impeller is spinning a lot faster than the turbine fluids wanting to hit it here on this part of the blade and then we're going to get a redirect of fluid going right in the same direction as impeller rotation now as you get closer to cruising speed and the turbine starts catching up to the speed of the impeller the fluid slowly starts creeping around it doesn't want to hit this side of the blade anymore it wants to hit this side of the blade if i don't do anything if i just hold the stator all the time it'll actually ricochet back in the opposite direction of impeller rotation and that would be bad it'd feel like somebody's hitting the brakes when you let off the throttle so what they do is they have that one-way clutch that's in here so when fluid wants to hit the back of it it's allowed to push the stator out of the way so it locks in this direction because we need to redirect the fluid flow for torque multiplication and it freewheels in this direction because when fluid hits this side we don't want it to redirect because it'd be going in the opposite direction of impeller rotation and that would be bad now we actually have a fourth part that we haven't talked about yet because back in the old days you know 50s 60s 70s that's all they had for torque converters they had an impeller that was engine driven turbine connected to the transmission and a stator that allowed for torque multiplication as we know fuel economy emissions make up a big part so they added a an additional component to a torque converter and that's the torque converter clutch and this is where there's a lot of different designs this is called a captive clutch and it's not unlike the multiple disc clutches that we just talked about just previously when you look at it it's just uh we just got um steel's friction steel there's two friction discs in this one and there's a thicker backing plate a little thicker so that way it can absorb the the force of the hydraulic piston this piece is a little cushion spring so that way when the clutch applies it doesn't just bang on that clutch assembly when the piston applies it will deflect this and allow it to kind of smoothly apply [Music] so this is the piston it's a steel piston large surface area with a large surface area with a little bit of pressure behind this thing will actually get quite a bit of force on this piston and because i could show you to seal that off they they have o-rings in there the o-ring for the middle is in this hub section and the outer o-ring is built into the piston when this piston comes up it's going to compress this clutch pack and this clutch pack is splined to the turbine right there so you can imagine these clutches the steels these steel plates are lugged to the cover of the torque converter and those friction discs are splined to the turbine and they got little cushion springs and so forth in there almost like a clutch on a manual transmission what will happen is when the time comes they can apply this piston and lock the converter housing to the turbine and if you remember the turbine is splined to the transmission's input shaft so once we're up to speed or you know we have to get going very fast on these late model units they apply these torque converters really quick and basically let the engine drive the input shaft of the transmission through this clutch assembly so here you can see the fluid to apply this clutch is actually come in right through the middle and that clutch will come up and apply the way it gets in there is through the input shaft so with this in there and there's two holes so i can cover my finger over one you can see that piston go up and down applied released applied released applied released okay so that is how this clutch works and as i mentioned when i apply this clutch i just lock the turbine when that clutch is applied this turbine won't spin i don't have that many hands available so i went ahead and put a c-clamp on this but you can see i can spin this assembly but when i apply the clutch it locks spin lock spin lock so that's the idea of this lock up converter is that when i apply this clutch that's in here when i apply this clutch assembly it's going to lock itself to this turbine this turbine locked to the cover it's going to drive the input shaft so i'm going to have an engine that's kind of bypassing the torque and driving the input shaft this lock up converter thing that's a big deal on modern vehicles we've got all these speeds now in these transmissions like a 10 speed they'll bring a lock up converter on in first gear second gear i mean they and they won't even just bring it on completely sometimes they'll bring out just a little bit and let it slip so a lot of strategy has gone into how these torque converter clutches work because what they're trying to do is make these vehicles so fuel efficient and we can't lose a lot of energy through creating heat and a torque converter so as soon as they can apply this clutch the less energy loss to a torque converter and the more fuel economy all right so this is that honda and what you know we hopefully understand the major parts the turbine remember turbine and t turbines are connected to the transmission stator purpose of the stator is to allow for a redirection of fluid flow during torque multiplication and it allows you to get torque multiplication and then the cover has the impeller built into it and then on the outside we've got our hub that allows us to center it to the transmission and also drive an oil pump and on the other side we've got a pilot that allows you to center it to the crankshaft and drive be driven by the engine's flex plate this whole assembly's welded together now let me just show you a couple little differences this this one here is a from the ford 6f50 it functionally if you look at it it's like huh don't look that much different to me i got a pilot got three mounting pads i got flats on this instead of a notches because this um just the way it drives the pump is different still drives a sprocket but when you look at the inside it's the impeller is still still got impeller a lot of brace by the way this gold color is brazing me they put like a powder in there and they furnace braise it they put in an oven and that's like soldering all these parts together not all torque vendors do that sometimes they just crimp them over and this is kind of a nicer option here's their stator this is their uh turbine so this turbine is a little different it's got these little tabs welded to it and those tabs grab onto this disc so instead of using multiple disc clutch assembly like we did on the honda and you know this is actually definitely a more common setup is using just one solid disc here and they're going to operate the torque cover clutch a little differently in this when this vehicle is operated with the lock up converter off what they do is they pump fluid in through the middle of this piston through the input shaft and the fluid enters the torque converter between the cover between this cover and this hydraulic piston where the friction material is and all that that's where they enter the fluid in so by pumping fluid in through this way it causes this piston to move away from the cover they do that on purpose that prevents this clutch from coming on and then when they want this clutch to actually apply they'll reverse that they'll bring the fluid in on this side and kind of it'll try to find its way back in a sense at least for a little bit through the middle and by doing that this piston is going to get the kind of a more of a pressure on this side of it it's going to drift towards the it's going to drift towards the cover and then when this piston comes into contact with the cover it creates a natural seal and then boom you get all that converter pressure working across this whole piston and uh you get a lot of force now this piston is lugged too that's what those tabs are doing this piston is lugged to this turbine so when i lock this piston to the cover i'm driving the turbine and the turbine is connected to the transmission's input shaft so this is a 6f this is a 6f50 ford transmission and so this is the input for it everything heavy so you can imagine when i apply this lock up converter and it grabs on to the torque converter cover which is bolted to the engine and and so forth it's going to deliver torque right directly into the transmission bypassing in a sense the action of the torque converter and that allows for what we call the torque converter lockup right so this is a little different than the honda the you can see the single friction surface that they've got there and it's a big plate that ends up covering contacting the housing this is actually a more common way for a lock-up converter things are moving to the multiple disc clutch type but this is probably still the most common setup so turbine with the big converter piston in there we still got our stator that's going to redirect fluid so the operation of the the torque converter doesn't change the only thing that's different is that piston all right that's that one and then over here this guy right yeah this is off the 10-speed ford 10-speed gm they both use this design and uh it's a lot different than these others it still has a stator impeller turbine we still have a hub that drives a you know a pump and all that stuff's the same still mounting pads and oh pilot for the for the uh back of the crankshaft but what makes this different is when we pull it apart you'll see a machine surface on the transmission side of the cover and built in to the turbine there's a flange that has the torque over clutch material on it so that's a little bit different this surface which is on an angle matches with this surface here so this is gonna probably create a little bit of um of a snafu for the remanufacturing facility they're gonna have to figure out ways to machine the surface smooth and and uh bond because they use heat and pressure and glued to bond these friction materials on it well now whatever they have is gonna have to do it on an angle so that's gonna be a little different stator's still a stator nothing fancy going on there the big changes is this flange right here on an angle and it and it's connected to the turbine directly it's not a separate piston and it allow and it has actually they move the the whole turbine assembly towards the transmission to apply onto that surface area to get this converter to lock up and that's something that's that's different on this side of it you can see they've got a ton of these pins and rivets and for in these springs to absorb damp the dampened vibrations it'll be interesting to see how the remanufacturing industry addresses this let's talk about some of the terms and tests and and characteristics that surround torque converters you might have heard the term stall speed that gets thrown around a lot when we talk about torque converters the stall speed actually does have a value for diagnostics a pretty good value and let me describe what a stall speed is first because to hear the name stall speed you might think that's when the engine stalls no it's actually not doesn't relate to that at all i think but i'm not 100 certain that it comes from maybe the aviation side of things in fact a lot of these parts when we start thinking the names impellers stator turbine those kind of have connections to the aviation industry but in an airplane or a jet or something like that the stall speed is like if you were to fly that thing towards space and it kept climbing and climbing and climbing you're wide open you're just blasting away going as fast as you can well eventually you're not going to climb any higher you're going to get to a certain altitude and you're going to stall the engine like install you're still going to have 100 output but you're just not going to get any more energy you're not going to get any more movement out of that plane so the same thing is similar with a torque converter the stall speed is is if i were to keep my wheels from moving break you know by applying the brakes or whatever uh so my transmission and my turbine because remember what's connected to the input shaft of this uh values this torque converter since i've got this big old input shaft here remember what's connected to the input of the torque converter is the turbine turbine drives this input shaft and the fluid coming from my impeller pushes up against the turbine and that rotation tries to drive my input shaft well during a stall test i'm spinning my impeller or my engine side as fast as it'll go without getting any movement out of my turbine so that means this engine is going let's say 2000 rpm but my turbine is not going any any faster so if you thought about what's happening to the fluid during that situation i've got fluid coming from my impeller to the turbine bouncing off the stator back in the same direction as my impeller back to the turbine bounces off the stator so it's impeller turbine stator impeller turbines say your impeller turbine stand we just get this loop-de-loop-de-loop-de-loop it's sitting there swirling like crazy right getting as much torque multiplication as i can i'm redirecting with force as much of that fluid from the turbine off the stator in the same direction as the impeller so i'm actually pushing on that that volume of fluid that it's moving i'm helping it out as much as i can with that redirected energy but there's a point where my engine is only so strong it can only throw so much fluid and it's only gonna get so much help so the engine speed is gonna climb up to a point maybe it's 1800 maybe it's 2000 maybe it's 2500 rpm and that's as high as it'll go i can't get it to go any faster that would be the stall speed so if you see like a spec in a book that says uh stall speed should be around 1800 to 1900 rpm so if you were to test that you would put it in drive you would be in a safe spot you'd apply the brakes it's hard you know a lot of force parking brake the whole works and go wide open throttle not half throttle not quarter throttle you go wide open throttle and what you're doing is you're applying as much force from the engine to this torque converter and having this spin as hot fast as it can go the impeller spin as fast as it can go with the transmission's input shaft spinning 0 rpm so it'd be impeller turbine stator impeller turbine stator it's going to climb as hopefully to that spec it's going to be in that range if it doesn't get to that range if it can't climb that high there's a couple things that could be wrong now i sometimes challenge the students in the thinking about this i'm like okay if i did a stall test and this let's say make it easy the spec is supposed to be 2 000 rpm and let's say the they'd perform the stall test and you got 2500 rpm out of it what could be wrong well in most cases what would be wrong would be as a clutch and the transmission is slipping not in the torque converter but in the transmission and you're actually getting input shaft rotation if you do a stall test and let's say 2000 rpm is still the spec and you're only able to get 1500 rpm or 1200 rpm what could be wrong maybe even less than that okay for one let's think about this stator if this what's the purpose of the stator it allows that fluid from the turbine the leftover energy to bounce off the stator blade in the same direction as impeller rotation well imagine if this one way clutch in there wasn't holding and it was allowing it to move that fluid that would be coming in there wouldn't be bouncing off of the stator blade and redirecting in the same direction as impeller rotation the fluid that's left over would actually get interfere with the impeller rotation so that if a one-way roller clutch was not holding in on your stator that could cause a low stall speed also another one is your engine performance one with the source of the rpm and the power is coming from my engine so if my engine is in need of a tune-up if i've got a clogged fuel filter and i'm not getting as much fuel clogged air filter you know a restricted exhaust timing that's off cam timing or ignition timing any of those things can lower the output of my engine and if i lower the output of my engine then i can't spin these parts up as fast and that's going to lower my stall speed think of the example i gave you with that above ground swimming pool that would actually that might clear up a little bit of confusion if you're still struggling with the topic a little bit so if i go back to my analogy with the above ground swimming pool and i had let's say four people or five people marching around the outside of that pool getting momentum and getting that current flowing and circular and all that stuff i'm going to give you a couple different options same swimming pool but we've got four middle schoolers in there that are 10 years old 12 year 11 years old haven't hit puberty yet they're not strong how much of a current and how much momentum of fluid do you think they're going to be able to create now let's say we take the saluki defensive line and you get four of their strongest guys in there and they're marching around this thing they'd probably be marching around that little above ground pool so fast that water would be pouring out the outsides so that's happening in my torque converter but instead of the middle schoolers and the football players i've got an engine with a amount of certain amount of torque certain amount of horsepower so a stronger engine will be able to drive these parts faster and the stall speed will be higher a weaker engine won't be able to achieve that we're just not going to get the strength and the momentum and the force of the fluid in here so the stall speed would be lower a lot of people want to think that like something in the transmission or the torque of it is slipping if you're got a low stall speed and the only thing that could be slipping is that one-way clutch because then you're not getting the redirection of that recycled energy from the turbine so most for the most cases if you've got a low stall speed you're dealing with a one-way clutch that's slipping or you're dealing with a engine issue if you have a high stall speed you're dealing with a something in the transmission that's slipping or you got a stronger engine maybe maybe you did a modifi modification to your engine but yet you didn't change anything in the transmission your stall speed might be higher now because of that so that is one thing that people will do with the automatic transmissions and diagnostics as far as a torque converter is concerned is they'll perform a stall test if the stall test isn't with inspect then they can kind of get a direction to look look at this big old haas of a torque converter this is off of an elson 3000 4000 series i got a couple of these donated and this you know here's our impeller big old mama and here's the big old stator in there you probably see why we got this bearing kind of destroyed itself on there surprisingly it didn't really damage the impeller side at all and here's the turbine and pull it out remember earlier i was saying that sometimes they don't braise these and you can see right here on this turbine they just crimp these over big chunks of steel so maybe that the size of it kind of allows them to get away with that on the impeller side it is brazed to it and then our lock up clutch is kind of the separate pressure plate assembly that we have here so there's our friction surface so that whatever life this thing had was didn't affect the torque converter or the it didn't affect the converter clutch at all and then if you were to rebuild this thing that says piston plate side and it doesn't say anything special on this side but this is the piston in here so it's telling you that when you go to put it together make sure you have it in that direction not in that direction i don't even know there's no way you can put it in that way because it's the hub will keep it away from the cover so but you know like they always say somebody will try it right so i'm not gonna try to pull this piston out but if i turn this over and slapped it on the table this piston would come out and uh i can change the seals on it so here we have allison's 3000 4000 series something you might find like a dump truck or something like that and it's kind of nice because they give you the capability to rebuild this thing so even in a heavy duty torque converter that would go in something like a garbage truck or like a big old dump truck or something like that the um the major components are still there we still have a turbine still have a converter clutch still have a stator to get torque multiplication and we still have an impeller now this thing's nice because you get to take it apart inspect it and buy parts for it rebuild it and you don't have to send it off to a shop you can go through and do all the testing and verification and measurement yourself to see if it's good or bad

Channel: siu automotive

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Id: Ijkh9vtgMIU

Length: 41min 58sec (2518 seconds)

Published: Fri Aug 07 2020