Did you know that we owe credit for one of the most advanced eight speed automatic transmission designs to to freshmen? Find out more here in this episode on the WeberAuto YouTube channel. My name is John Kelly, and in this episode we are going to be covering the Aisin eight speed rear wheel drive automatic transmission. This is one of only about three rear wheel drive, eight speed automatic transmissions that are in production and use at the time. The other two transmissions that are in use are the General Motors, 8L90, and the ZF or Zed F, eight-speed automatic transmission. I forget the model number. Maybe one of you knows what that is and can put it in the comments. But there are only three and the General Motors transmission and the ZF transmission use for planetary gear sets to achieve the eight speeds which is pretty typical of two forward gears per planetary gear set. But the Eisen automatic transmission is a totally unique design, it totally blew my mind. And I'm really excited to show it to you here today. Regarding the Frenchman, there are some designs of planetary gearsets that are used in this isin eight speed automatic. By the way, this is an eight speed automatic that is used in 2008 and above Lexus rear wheel drive vehicles. And it's also used in the Cadillac CTS-V their high performance Cadillac CTS with the eight speed automatic transmission. So let's get to understand this unique design for this eight speed transmission, we need to go back in history. And there were four patents that were filed for different designs of planetary gearsets. And I want to walk you through all four of those, which leads to this eight speed transmissions, the transmission. Two of those patents, which were big, major designs were done by freshmen and a long time ago. One of the patents is 66 years old. Another one is 26 years old. And then there's a Japanese guy that worked for us incorporation that in 1999, so 16 years ago patented another variation of this design. And then we'll start with the most basic design on the planetary gearset and build up from there. So the first planetary gear set to understand so that you can understand this eight speed automatic transmission is the simpson gear set. The Simpson gear set was developed by a Mr. Howard Simpson, Mr. Howard Simpson, according to what I was able to find on the internet, was a engineer for Henry Ford, back in the early days of Ford Motor Company, and he died in 1963. But in 1950, he patented a compact design of planetary gear set that we now call the simpson gear set, and I've got a Simpson gear set right here in front of me here. And the simpson gear set involves a set of planetary internal gears, ring gears, annulus gears, whatever terminology you want to use to describe those. So two ring gears. It also consists of two planet carriers. And I have a separate YouTube video on just planetary gear set operation and how all that works. But the simpson gear set, we've got to ring gears to Planet carriers. And then we have one common sun gear. Now, this sun gear, as you can see, has a common shaft it's all one solid piece, it turns one speed. They're connected together. This son gears a little bit larger diameter than this one, which gives us a different planetary gear ratio. So I want to put this Simpson gear set together. The Simpson gear set was a three speed and it was done with this configuration and so some of the early three speeds used by Ford and General Motors and Chrysler and so on. Used The Simpson gear set as as a three speed transmission. And so we've got because we're gonna get some gear in there, the ring gear planet carrier and the bottom son gear. And then we have the tops on gear all on the same shaft with the upper planetary carrier, and then the upper ring gear, just like that. Okay, now this is a three speed and I just want to quick quickly show you the the three speeds. So I'm going to make three little marks here, I'll make a paint mark right there, another one right here, and another one right here. And so on the three speed gear set, let me zoom in here just a little bit. We have devices that will hold one or the other planetary carrier to give us the different gear ratios. So for first gear, we're going to hold this bottom carrier and turn the top ring gear and it's about a two and a half to one gear ratio. So I'm going to turn this upper ring gear about two and a half times to get one full turn of the output shaft. So here we go. There's one, two and a half, two and a half times up here to get one turned down here. All right, let me go back, line up our marks again. Here we go. They're all lined up. Second speed is about one and a half to one. So now we're going to hold the upper sun gear for moving and turn the upper ring gear. So here we go one and a half. So here's one and a half. And so we've got two speeds out of the three speeds. Third speed is just simply direct drive, we drive, the ring gear, and the carrier the same speed. So let me line those marks up again. Here we are. Upper ring gear upper carrier, here we go. Just one turn. In equals one turn out. So just real quick and simple. A Simpson gear set patented in 1950. This gear set was used in automatic transmissions for many, many years. And as a three speed, but then in the late 70s. And up through all of the time that we had four speeds. All they did to make a four speed out of this was to take the simpson gear set and throw an overdrive planetary gear unit in front of it. So in the back half of the transmission would be the three speed and it would have an overdrive unit, a two speed overdrive unit in the front. So it would give us four speeds, direct drive for first, second third, and then it would be overdrive. overdrive fourth gear would be from the additional gear set. Chrysler's put the three speed in the front and the overdrive in the back. There's there's different variations of it. But the simpson gear said been around a long time. That is a real basic automatic transmission design, but it was universal at the time, because prior to that we had to have an individual gear set, planetary gear set for each set of speeds and so a two speed automatic transmission, the power glides and so on. They only had one planetary gear set which gave them one under drive gear and one direct drive. But in in 1949, there was a Frenchman named Paul ravid. No Paul raveneau. And he and he invented what's called, or what we refer to as the raveneau gear set and the rabanal gear set is a four speed so the Simpson was a three started a three speeds raveneau in 1949. That was one year before Simpson and his three speed invented this four speed planetary gear set. And from what I've read on the internet, and I could be wrong because it's it's the internet. It wasn't utilized because we didn't have precise enough hydraulic controls for timing of applying and releasing clocks. And bands and so on to have a smooth four speeds as far as up shifting and down shifting. So it just kind of sat around until 1999 when we started developing six speed automatic transmissions, so the rabbit rabbit is playing say right revenue gear set is a four speed gear set. But to my knowledge, it wasn't used in any four speed automatic transmissions. I could be wrong I probably am. But I'm not aware of any right off the top of my head. It was used when it was we turned transaxles transmissions into six speed automatic transmissions. And so I want to show you the raveneau gear set first. And so the revenue gear set starts with and this is the back half by the way of this eight speed automatic transmission. So we're using a four speed raveneau gear set in the back of an eight speed automatic. This is the output shaft of the railroad rear wheel drive isin automatic transmission, this particular model in the Lexus IS CALLED THE a 80 280 e. The E means it's tool drive. If it was an age, it would be all wheel drive, f would be four wheel drive, and so on. So we have our drive shaft flange uses the flexible coupling rather than U joints. And if this output shaft turns of course the vehicle will move. So let's let's get this set up in the holding fixture I have here. So I'm going to set this right here, I've got a label on here labeling it as the output shaft and it is free to turn I'm just going to stick the the output flange on the back here and put the nut on there just so it's easier to see when the when the shaft is turning now connected to this output shaft in a Rab raveneau gear set is a ringier so we've got a just a simple ring gear here that connects to the output shaft. So if this ring gear moves at all the vehicle moves. So this this is referred to in this eight speed transmission as the rear planetary gear set. And down inside of that when we take this back off, we are going to have what is known as the intermediate shaft come down so we have three three shafts on this transmission and the input shaft the intermediate shaft and the output shaft. So as the name implies, intermediate is in between the intermediate shaft has a set of clutch plates right here called the C two clutch. And it will be used in the rabbit no gear set here in just a moment. So we've got a ring gear, we've got a shaft, the intermediate shaft and then the unique part that makes it different from the simpson gear set is this planetary gear carrier. So this carrier, well remember Simpson gear set at a common sun gear to carriers and to ring gears. The raveneau gear set has one ring gear one carrier, but then it has two individual son gears to some gears. Okay, so inside of this planet carrier. It has as you can see on the outside it has the planet gears. This planet gear is a really long gear it sticks all the way up in about right there. So that's called the long planet. And then it meshes just off to the side here it's kind of hard to see. Try to show down the middle here. Also, the lighting isn't very good. But it meshes with a short planetary gear set. So we've got the tall planetary or the tall planet gear here the short planet gear here, the tall planet gear meshes with The front sun gear and the short planet gear meshes with the rear sun gear. The fits down in here so, arap raveneau gear set has one ring gear, one planet carrier with long and short pinions. And all by itself, there's no power being transferred through. But we're going to take our rear son gear as it's called in this gear set, and we'll put it all the way down in and let it mash. And that rear son gear by the way has a clutch hub for what is called the C one clutch that splines to it. So we can turn the that rear sun gear independently of the front sun gear. The front sun gear right here is connected to this clutch housing. And it will spline to another clutch housing that has a C three clutch in it. But it allows us to independently turn the upper son gear. So between these two housings, we can turn the two son gears, the upper or the lower sun gear with this piece inside the upper sun gear with this piece on the outside. All right, now we were let's not forget, we're talking about an eight speed automatic here. So far, we are looking at a route revenue gear set that can give us four speeds. And so let's look at what the four speeds are. And let's let's make let's make some marks here. So I'm going to make a mark on this, this ring gear right here. And on this holding fixture down below it, the ring gear turns the same speed as the output shaft down below it. I'm going to make a mark on the planet carrier right here. And on this shell that turns the front son gear. And then on this other shell the that turns the rear son gear. Okay, so for first gear in a four speed raveneau gear set we are we have a gear ratio of almost two and a half to one. So very much like that Simpson gear set almost two and a half to one. And we will hold the carrier from turning. And we'll do that with the be to break that would come in here and hold that and then we will turn the rear son gear. So that's this inner set of splines. And so if I let's get our marks lined up here again. So looking down here, I'm going to turn this inner piece two and a half times to get this ring gear to turn one time and that's our first gear. So here we go. So here's one, two, and half. So there's our first gear two and a half to one. Okay, now let's let's bring it back. Second gear, we're still going to turn the rear son gear but now we're going to hold the center son or the center son gear the front son gear from turning. So now I'm going to hold this son this shell that connects to that front son gear from turning and I'm just going to turn the rear son gear. This should take one and a half turns to turn the ring gear in the output shaft one turn so one and a half turns with the rear sun gear to get one one turn of the output shaft so here we go. There's one and a half. So one and a half turn so that that is second gear on a rabbit raveneau for speed gear set. Now third gear is is pretty easy. We We're going to drive the front son gear, which is this housing here connects to it, and the rear son gear, so that's this inner housing, we're going to drive those the same, the same speed. So that's pretty much locking those two together, we have direct drive, one to one. So there's our third gear on the raveneau gear set, and our fourth gear, which we get an overdrive, which is the big bonus over the Samsung Gear set, the raveneau gear set gives us an overdrive. And so this a usable overdrive. To get overdrive on this gear set, we will hold the front son gear from turning, and we will turn the carrier. So let me let me get the marks line back up here. Where's the mark, I must have rubbed it off. Alright, I'm going to just make a mark right here under the be to break sign. And we'll just use the be to break sign also. So I'm going to hold the front son gear, which is this housing, turn the planet carrier, which is this piece that has the be to break that can apply it. And now the ring gear and the output shaft should turn faster than the carrier that returning and we should get a 0.685 to one gear ratio. So in other words, we will only turn this planet carrier, almost seven tenths of a turn to get one full turn of the output shaft here. So here we go. Notice the ring gear is turning faster than the planet carrier. We have one full turn coming up. Right there we have one full turn of the ring gear. But notice if I spin the whole assembly around, we only had point 685 turns of the planet carrier. So this is a raveneau gear set, we've got four forward gears, and of course, we have reverse. in reverse. If we hold the carrier from turning and turn the front son gear will have a reverse gear ratio of about a little over two to one. So notice now there even though we turn the front son gear forward, the rear ring gear of course the ring gear turns backwards, a little over two turns 2.176 turns to one to give us reverse. So the rear half or actually it's about the rear two thirds of this eight speed is an automatic transmission is a four speed raveneau gearset. All right, now here is where things get interesting. How do we get eight speeds now. There was a French gentleman that came along and in 1989 patented a six speed planetary design a six speed transmission design. And that six speed design is called the lapel ta transmission design. And the guy's name is Pierre lapel TA, a French engineer. And like I say in 1989 he took the raveneau gear set so we build upon what Paul Ravenel developed and he put a simple to speed planetary gear set in series with it and created the six speed. So if any of you are driving a six speed front wheel drive transaxle chances are it's a lapel ta designed and patented transaxle. So we have for the front gear set on a six speed automatic transmission we have another ring gear. We have another planet carrier and we also have another sun gear. So just one more set. One more set of planetary gears. Well, what lapel ta did is he figured out how to not just do a two speed overdrive have a four speed transmission, it's more involved in that. It it actually allowed for six nicely spaced gear sets. So that's what are gear ratios. And so what I'm saying is that's different than the old Simpson gear set that had a two speed overdrive either in front or in back of it. This uses the two speed, planetary gear set to hold and drive different pieces of the raveneau gear set it at different speeds to give us six forward speeds rather than just the four that you could get out of the revenue. And he, like I say, he patented that design in let's see 1989 is when he patented that design and it's been used ever since. The see the GM 6070 is the and all the variations of the 6070 is the lip LTA design, the Ford six f 50. And all the variations of that are, it's the same thing. And there there are others, both front and rear wheel drive, that use this lapel ta design. Well, lapel ta was still alive, obviously in 1989. And I really don't know if he's still alive today. Maybe one of you viewers could tell me I could not find it on the internet if he was still still alive. But I did find an article that said in 1999 10 years after lapel Tia patented his six speed transmission. three independent engineers came up with an eight speed design that used the Peltier a six speed components. So what I'm telling you is, we take the six speed automatic transaxle, that lapel ta designed, which uses a simple planetary gear set in series with a raveneau gear set to give us six speeds, they took that design and here's the mind blowing part. They didn't add any additional planetary gears. But they figured out a way to get to more forward gear ratios. Nice to use forward gear ratios usable gear ratios out of these exact same parts just by holding and driving existing pieces at some different speeds. And so I'm going to show you how that is done. This actually took me two weeks I disassembled this transmission in an afternoon was no big deal. But it took me two weeks to figure this transmission out as to how it gets all of its gear ratios. And so I want to share that with you. So let's put the rest of it together here on the on the bench. So we've got our raveneau gear set, I'm just going to take a the front ring gear and set it in. And then I'm going to take the front planet carrier and set it in. And oh, wait a minute, there's one thing I wanted to show you show you on this design, this front input shaft is splined directly to that intermediate shaft. Let me just show you that real quick. Because you need to you need to see that I think to understand what is how this eight speed actually works. Okay, so here's our intermediate shaft like I showed you before. Notice our input shaft has teeth that spline directly to that out or to this intermediate shaft. So this is odd. As far as any other transmission I've seen. We are directly driving the intermediate shaft with the input shaft we're directly driving the front planet carrier with this input shaft now, I'll show you how cool that is and why that helps us get Eight gears here in just a moment with some other things. So let me set our raveneau whoops revenue ring gear down here. Our raveneau planet carrier are we're sun gear, or front sun gear. Oh, I forgot. There's one spragg in here. One way clutch that is only used during the one two shift to make the transition smooth. So here's our front sun gear, and our clutch hub to connect to the rear sun gear. Here's our front planet. Planet ring gear. And then here's our front planet carrier. And it's got to go down and spline to that intermediate shaft. There we go. So we had lined up a few things there to get it to drop. All right now, a unique design on this eight speed is the front sun gear is actually splined right to our oil pump, stater support. And of course, it doesn't want to line up. There we go. So the sun gear never turns, this sun gear is held solid always. So we will put the sun gear down in the planet carrier, we will put our oil pump housing down in there we go. Didn't mean for it to drop that quickly. That's not really good on bearings. The only thing that I didn't put on that I will show you here is it has a this clutch drum that goes underneath the oil pump housing. And these teeth here spline to this front son gear, housing it splines directly to it. And then there's a C for clutch that connects to the front planet carrier, there's a before break that goes around the outside of this that can stop it from turning. But all of this just connects to that front sun gear. Okay, so our front planet planetary gear set is right here, it's just a simple gear set with the sun gear always being held solid. And so to hold that solid, I'm going to I had to get creative on this video to figure out a way to hold that solid and turn the other pieces. And so I've got a just for demonstration purposes, I've got a vise over here, there is a hole right here in the the clutch the the oil pump housing and I'm just going to lock that screwdriver in there that will keep the oil pump housing from turning which basically is holding that sun gear from rotating. So, our front planetary gear set the front sun gear is always held the input shaft is connected directly to the planet carrier. And so, if you think about this for a moment, the the input shaft and the front sun gear or the I'm sorry the input shaft and the front planet carrier right here are splicing together and the carrier and the input shaft just turn at a one to one gear ratio with the input shaft of this automatic transmission hook store torque converter and through the through the converter to the engine. The only gear ratio change in that front gear set is right here between between the carrier and the ring gear. So if I turn this carrier on Notice if I turn the carrier the ring gear right below, it turns a little bit slower. And it actually has a gear ratio of about 1.863 to one. And so all we have from the front gear set to feed the back for speed gear set our two gear ratios, one to one which is directly through our input shaft and all the way through our intermediate shaft to that rear c two clutch. And then we have through gear reduction, the sun gear that can be connected to that front. I'm not saying here we have this ring gear, the front ring gear that through this housing right here, which drives the front sun gear can drive the sun gear at at slower speeds. It also has a clutch on the inside of it that can connect to that rear sun gear clutch hub. So the front planetary gear set can drive the front, rear or front sun gear of the raveneau gear set, it can drive the rear sun gear or the revenue gear set, it can drive them at a one to one gear ratio, if we lock it up, or it can drive it at a 1.83863 to one gear ratio. So the front planetary gear set never changes gears, it never shifts. All it does is creates two. What's a good way to say this, it creates rotating components that spin at two speeds. One at direct drive with the input shaft one turn in one turn out one at a slower speed 1.863 to one gear ratio as compared and slower than the input shaft. So there's never any clutches that, that apply in release to up shift or downshift the transmission off of this front gear set that whole front gear set, the only reason it's there is to create two rotational speeds that we can use to drive the raveneau gear set in the back. Now, this design right here was actually a modification of the six speed lapel ta designed. And this was done by a guy that worked for isin Corporation. I send transmissions in Japan, in 1999. He and Mr. lapel TA and one other guy all kind of came up with this idea for the eight speed version of or eight speed modification of the lapel ta design. All in that same timeframe. However, the guy at Eisen was the first one to make it to the patent office, and he got the first patent. And this transmission the ice, an eight speed automatic transmission is the only one that's ever been produced off of that patent designed now Miss Mr. lapels, da He also received a patent but it was for a variation of this that has never been produced. And the other guy also received a patent. But it was a different variation that has also never been produced. This is the only one that So once again, this took the six, it took a four speed raveneau it threw in the two speed simple gear set in front, the lapel ta patented to make a six speed and then without adding any planetary gear sets, they figured out how to get to more gear ratios to give us an eight speed. So this eight speed transmission is lighter has fewer parts fewer clutches than the GM eight speed and the zet f the Zf. German eight speed rear wheel drive transmission, which is a huge benefit is as far as fuel economy and emissions are concerned. Okay, well, let's take a look at all of the gear ratios then through this eight speed transmission. And how did they get those two extra speeds that the six speed lapel Tia design did not get. So I'm going to back the camera up just a little bit here just a moment. All right. The first gear I want to show you is just reverse. And so reverse. We have the C four clutch which is this clutch housing that connects right here that's directly connected to the input shaft and it's going to connect to that front Son gear through this housing right here, it will be applied. And then we also have the be to break applied and the be to break is this piece right here. And that'll give us a gear ratio of 2.176, we are doing nothing more than using the raveneau. reverse gear ratio, it's exactly the same gear ratio here on the raveneau. And so I'm going to turn the input shaft, I've installed a chisel holder on the input shaft here to make it easier to turn. And we've got the marks right here of our output shaft a ring gear, line up with the holding fixture here. And so if we turn the input shaft which would turn the C four clutch, which would turn this housing and hold this be to break, which holds the planet carrier, so basically, we're holding the rear planet carrier, The Revenant gears at returning the front son gear, and we just simply get reverse. And so we would have one, two, and just a little bit more 2.176 turns of the input shaft to get one turn the output shaft in reverse. All right, so we don't use anything in reverse except the revenue gear set. Now let's go to first gear, and in first through fifth gears, we are going to apply the C one clutch and the C one clutch. Let me line our marks up here again. The SI one clutch is inside of this housing, it's the one that connects to that hub that goes down to the rear sun gear of the raveneau gear set. So we're going to be we're going to be turning the rear son gear for the first five gears out of the eight on this raveneau gear set. And to make that happen. I need to connect this ringier housing to that clutch hub housing inside of here. And so I've got a little sheet metal screw and a hole I've drilled that I can use to connect those two together. Now I know you're not supposed to drill holes in automatic transmissions. And the last time I did this on a demo, I got all kinds of comments from viewers saying no, you're not supposed to drill holes and has no way to treat a transmission. These are training transmissions, they're never going to be put in a vehicle. There'll be fine. This This works great without having any type of hydraulic clutch piston to apply a clutch that's not even in this housing. We're just going through the power flow here. So let me get that screw installed. Okay, so first gear, we've got a gear ratio of little over four and a half turns to one that's an impressive gear ratio, it's you will get some rapid acceleration out of that. And for first gear, we've got the C one clutch applied, that's down in here that connects this front ring gear with a gear reduction out of the front gear set of 1.863 to one and it connects it to the front. I'm sorry, the rear son gear in the rabbit no revenue gear set and we have this f1 one way spragg or that's mechanically held also, so I'm going to hold that holds the carrier so basically we're turning the rear son gear holding the carrier of the revenue gear set, and we're turning the rear son at a gear reduction of 1.83 to one off of the front gear set. So it's not the same as the first gear ratio obviously of the revenue because its first gear ratio was two and a half to one roughly, this is four and a half to one. So we've got almost an additional two to one reduction out here. So I should I should be able to turn this input shaft, four and a half turns to get one turn out of the output shaft. So here we go. 1234 and half turns the input shaft get one turn the output shaft so that's first gear. Second gear we keep the C one clutch applied, and now we apply the b1 brake. The b1 brake is the brake clutch clutch pack that goes around this housing that splines directly to the housing the hole goes to the front planetary gear set of the raveneau gear set. So in other words, we're going to hold this housing from turning, which is the front sun gear. In this transmission, it's actually called the central sun gear because we the front sun gear is the simple one. So we've got three, three sun gears, the front sun gear, the center sun gear and the rear sun gear. So we're going to hold this, we're going to hold the center sun gear, and we're going to turn the rear soundgear. So we're holding the front, turning the rear, the gear ratio is 2.7 to one. So here's our mark down here. So here's one, two, and about three quarters to give us 2.7 to one second gear ratio on this eight speed, transmission. Third gear, we keep the C one clutch applied, we apply the C three clutch, well the C three clutch is the clutch that connects the ring gear of the front gear set to the center sun gear of our transmission here of our planetary or revenue, no planetary gearset. So to do that, I'm just going to take a paper towel and water it up and shove it in here acting like it's the clutch plates connecting these splines to the internal splines of this housing. So I'll put that in there, right there. Third gear ratio is 1.8 turns of the input to one turn of the output. So let's line our marks up right here. And so we've got the C one clutch, turning the rear son gear, we've got the C three clutch turning through this housing the front son gear, and that gives us in the raveneau gear set a one to one gear ratio, but it's being driven off of the front planetary gear set at a regear reduction off of this ring gear and the planet carrier of 1.86321. So even though this is in direct drive in the planetary gear set, it's still under driven by the front gear set, and we get a 1.8 to one gear ratio. So here we go. Here's one turn, and almost two, and we've got 1.8 turns to one of the transmission. Now, you'll notice there that we just locked these two together to give us a direct drive. Now for fourth gear. Remember fourth gear on the raveneau gear set was the overdrive of 0.685 to one, we're not ready for that yet. Our fourth gear on this transmission is 1.46421. So third gear was 1.8 to 1/4 gear is 1.4 to one. So the way we get that in fourth gear is to keep the C one clutch applied, turning the rear son gear and then also apply the C four clutch or the C four clutch is this clutch right here that connects to the planet, the top of the planet carrier. So I had to get inventive. To make this work in a demonstration here. So here I go putting some more screws in. And then a paperclip. just for demonstration purposes. I know this isn't how it's really done. In the transmission. It's done with a clutch pack. But the point is, it's going to connect the C four clutch inner splines to this hub, which drives the front sun gear to its outer splines. And this fourth gear is unique and this is one of the things that this eight speed design does that's differently than most transmissions that you'll ever see. Most transmissions with planetary gearsets we hold One thing from turning, we turn something that's connected to the engine. And then the third piece of the three piece planetary gearset. drives, eventually the tires and makes the vehicle move. Well, notice here in fourth gear, it's not direct drive, we've got a 1.4 to one gear ratio, we are not going to hold anything from turning. So instead of holding something from turning, we are going to take the C one clutch that's driven by the ring gear of the planet carrier, which is driven at a reduced speed from the input shaft of 1.83 to one, think of that as being the one that would normally be held. But we're not going to hold it solid think about as we're allowing it to slip. But we're only allowing it to slip at a reduction of 1.86321 versus the input shaft. So as I turn the input shaft here, let me get the me get the marks lined up here. Oh, I forgot to take the forgot to take my paper towel out for the for the C three college. Okay, so I'll put my paperclip back in. But it up around the the sheet metal screw I'm not supposed to have in there, or the cabinet screw. And now we'll line our marks up again, right here, get the tension on the just a second have to get everything lined up just right to start. Okay, so here's the unique thing that we never did on the six speed. And that is to not hold anything solid. We're going to allow it to turn out we're going to allow it to turn. So this gear ratio for fourth gear is 1.4 to one. So here's our marks at the output shaft. Here's our input shaft. So now if I turn this there's one point for roughly one and a half turns of the input shaft to one turn of the output shaft. Now you heard my paperclip rattling on the clutch housings here, just ignore that but I couldn't figure out another way to connect these two pieces together. And it's such an unusual design that I wanted you to see that. If you'll notice, as I turn it the the ring geared is turning instead of being held solid, the planet carrier is turning out a one to one gear ratio. And that gives us a different gear ratio than we could have ever had on that six speeds. So there's that is our fourth gear. Alright, fifth gear. fifth gear is another one where we don't hold anything solid from turning with the planetary gears. So fifth gear, fifth gear, we have both the C one clutch and the C two clutch on at the same time. So the the C one clutch is in here. The C two clutch is the clutch clear down to the bottom. So the intermediate we've got the input shaft that went in connected to the intermediate shaft and then it went to that clutch drum and the bottom down here. That clutch drum when we apply that clutch, we'll connect it to the planet carrier. So I have another sheet metal screw that I'm going to install and connect the inner and outer splines. Let's see if that does it. I think so. Okay, so let's line up our, our marks again. Down here. Here we go. So fifth gear, we've got a gear ratio of 1.2 to one. So we've got some tiny little gear steps here. Remember fourth gear with first gear is this gigantic four and a half to one and second gear is roughly half of that 2.7 to one, but then third gear 1.8 fourth gear 1.4 fifth gear 1.2. So I should turn this input shaft 1.2 turns so here's one And point two. Let me do that again as I'm clear back here, so here's one and two tenths more or less than a quarter turn to give us one turn of the output shaft. So that's fifth gear. Now sixth gear on this eight speed automatic transmission is direct drive, straight through direct drive of all the components. And we do that by applying the C two clutch which is already applied with my little screw down in the bottom here, and the C four clutch will the C two drives the the raveneau carrier, the C four clutch is the clutch that turns the raveneau front some gear. So all I have to do Oh, and I have to release the C one clutch. So let me take the screw out of the C one that was holding it applied. So what we're going to do is turn the planet carrier of the raveneau gear set and the front son gear of the planet or the raveneau gear set the same speed. And so that is done through the C four clutch that turns the ring gear. Let's see, no the C two clutch down the bottom here turns the planet carrier and the C four clutch which is our direct input that turns the front son yours we're going to turn these two pieces the same speed. So let me line our marks up. We're going to just simply turn these two pieces. The rear piece is turned by our input shaft, the front piece is turned by Well, my paperclip contraption here, so let me hook that back up. Okay, so let's get our lot marks lined up here we go to simply a one turn n equals one turn out gear ratio. So we line those up again. So I'm right over here where I start, one turn n equals one turnout. All right now that sixth gear is our direct drive. That means seventh gear and eight gears are overdrive and double overdrive. So seventh gear, we keep the C two clutch applied in the bottom. And now we apply the C three clutch. Well the C three clutch is this clutch housing right here. So let me take out the my paper clip. demonstration tool here. We will put our wadded up paper towel back in to give us an engagement of the front planet ring gear to the center sun gear. And the C two clutch drives the rabbit no revenue carrier. So let's line our marks up here. Okay, line the marks up right there. And now this is overdrive, and our overdrive gear ratio is 0.8 to four. So eight tenths of a turn a little more than three quarters of a turn up here should give us one turn down here. So I'm starting right over here. There's half three quarters, eight tenths of a turn of the input gives us one full turn of the output that's our first overdrive in this eight speed is an automatic or second overdrive we keep the C two clutch applied and now we apply the B one brake or the B one brake. All it does is stop this front sun gear through this housing from turning. So let me pull out my paper towel that we use to apply the C three clutch with and now our gear ratio is for final overdrive 0.685 which is exactly the same gear ratio as the raveneau gear set overdrive gear ratio it's a pretty low are pretty tall, overdrive zero point 685 so I'm going to hold the front son gear from turning, we're going to turn the rear planet carrier. And I should be able to turn the the input shaft a little more than half a turn. So right over here would be half a turn, somewhere around here would be point 685. So here we go. Output shafts been a really fast marks are lined up and point 685 almost point seven turns of the input shaft versus the output shaft. So that gives us eight forward gears and reverse. And once again, the the thing that's unique about this transmission is the three gears that we don't hold and turn pieces of the planetary gear set. We allow those pieces to not slip but to turn at a slower speed. And those gears are fourth, fifth and seventh. And because of this design, this guy at isin that got the first patent on this HP design. They were able to go to market and Lexus has had an eight speed automatic transmission since 2008. The GM one just came out this year in the Corvette and in some of their trucks and SUVs. The Zed f the Zf, German one came out in 2013. In some Chrysler products and other vehicle manufacturer products around the world. I understand Honda or Acura has an eight speed automatic and some accurate but it's not a planetary gear set design I believe it's the automated manual transmission, which I will do a separate video on Honda automatic transmissions. So this has been a demonstration of the very cool isin eight speed automatic transmission. Once again, we we owe credit for this transmission to two freshmen from very long time ago. Mr. ravak, no revenue from 1949 in his patent, Mr. lapel da that put the simple planetary gear set with the revenue gear said to give us six speeds in 1989. And then the guy from Japan in 1999. That patented this eight speed, design amazing stuff. And we're going to see nine speed and 10 speed transmissions here. Not too long in the future. Chrysler already is using a nine speed and there's a joint venture between GM and Ford to make a 10 speed for their trucks and so we'll see what other designs are used and how they get nine and 10 speeds out of some of those future ones. Thanks for watching. Have a good day.
