These video's are a must for everyone that has an more than average interest in automotive mechanics. I hope they stay online forever, there's nothing like it out there. Of course when you needed 2 weeks to figure out the inner workings of this transmission, its pretty hefty to fully understand all of its workings in just one hour. I hope you'll be making videos like this for a long time.
Nice job. I don't feel so bad at backing up and re-watching parts of this, after watching you have to really dig deep to get it right. Masterful, truly amazing. Thanks!
Professor Kelly in 2016 when Land Cruiser moved to 8 speed I didn't understand what was the benefit of the two extra gears. That tiny gear change can improve fuel consumption by 11%, that's indeed mind-blowing. You explained it so clearly which I couldn't find anywhere else. Thanks. :)
Awesome video Mr. Kelly. I just can't imagine the minds of the people who can imagine and create such complex mind blowing pieces of engineering marvel. Thanks again Mr. Kelly for this video.
I just recently purchased an ISF with this transmission I went up to see my parents they live up in a mountainous area near Tahoe at 75 I’m turning about 1800 to 2000 RPM returning about 26 miles a gallon out of a 5 L V8 with this transmission!
Hi John, excellent description of this Aisin Transmission. I can vouch for the fact this Transmission is also used in the VW Touareg as well. Keep up the Good Work. Garry from Australia
That Aisin 8sp reminds me about tractor transmission, where they do fun things with torque splits a lot. They have main shafts and they have few secondary shafts that use torque in the other ways to make new gears. I've read about some prototypes of mechanical-electric transmission hybrids, where electric motors are used for driving those secondary shafts to simulate CVT ratios. Thank you for your channel! I'll dig it up. I'd like to invent some usable CVTs for high torque/high speed applications..
Well done and excellent education on the system workings of the 3 systems .The components look stronger than expected. Whe i noticed the time on your computer i realized why the shop was so quiet thanks for staying late to do this can't believe its 5years old !,
Mr. Kelly. Thank you for this awesome explanation and the effort you put into it. I learned a lot from your descriptions and you clarified some doubts I had about the Lepelletier design.. Regards,
Brilliant video as always, John. I've learned so much from your excellent explanations and demos. Interesting to note: the 2016 BMW X1 model will have the 8spd steptronic AISIN transmission. This is their FWD biased architecture that has Mini roots (platform). Keep up the fantastic videos!
The mercedes benz 722.4 and I think the 722.5 also uses a ravigneaux planetary gearset. It was fitted in vehicles in the late 70s up to mid 90s It´s a very interesting transmission to look at
Regarding your comment about Ravigneaux gearset, the GM "Hydra-matic" 4L30E has a Ravigneaux gearset, the planetary carrier is the output drive to the prop. However it does only uses 3 speeds from the gearset, the 4th speed is an overdrive and is attached between the torque convertor and the main casing. This transmission was used circa 1992 to 1999, although probably not in US models, it was used in European models in the Vauxhall/Opel stable. Interestingly this transmission was made in France for GM.
I just got through explaining everything you have explained in your video to my wife and she understood every single word just before she dropped off to sleep. Just kidding of course.... I have a Chrysler 300c with an 8 speed transmission. It's amazing how so many inner and outer gears can be so accurately machined so they all fit perfectly together. The tolerances have to be amazing and the machines that make the gears. Now I have a little idea as to what a complicated mechanism is moving my car smoothly down the road.
Holy shit, it took you two weeks to figure out how it works? I wonder how many weeks it took those 3 guys to figure out how to get 2 more gears out of the same set of gears. I can't comprehend the level of ingenuity.
Cool, John. I see that the Ravigneaux works the same way as the Borg Warner / Fordomatic from 1950/51 with the only major difference being those old sets were 3 speed, they did not have the "drive carrier / hold large sun" overdrive gear. The Ravigneaux 4 speed drives the carrier and small sun for 3rd gear, the BW/Fordomatic drove the small sun and large sun, the effect in both cases is to lock the train together giving a 1:1 ratio. I see how the 6 speed Lapelletier is a simple adaptation of the 4 speed Ravigneaux with the additional planetary set in series. Now I see how the Aisin is an adaptation of that Lapelletier. Thanks!
Dear WeberAuto, Thank you for what I consider the best video on youtube explaining the history, progression, and engineering related to the automatic transmission. You must be a great professor at WSU as your presentation is detailed and readily understood by most users interested in gearing and transmission technology. I found the detail on the Aisin AA80E to be very informative and also made me think about it competition: GM 8L90E and ZFHP. The Aisin uses 3 planetary gear sets to achieve 8-ratios while GM and ZF use four. In addition to my mechanical background, I am also a computer nerd and use binary computations all the time. To me, it seems logical that an 8spd Aisin can be produced using 3-inline gear sets: 2x2x2=8 (2 x 4spds) That being said, why does GM or ZF not use four gear-sets to produce an 16spd trans?.....2x2x2x2=16 Could be possible redundancy in gear rations or OD of ring gear being too large for application and achieve even spacing? Any thoughts? Or am I off-base in believing that 4 planetary gear sets can achieve 16spds? PS: Heavy duty trucks have been using the x2 multiplier since the 80's or earlier (even Corvette offered a 4+3 manual) Interested in your professional comments. Thank you, Alan - Automotive Engineer
LSmiata Thanks for watching and for your nice comments. Each planetary gear set is actually capable of delivering: two under-drive ratios, direct-drive, two over-drive ratios, and two reverse ratios. The more gear sets you use the more expensive, heavy, and complex the transmission becomes. I know that cost and weight are the two main factors in design. Patent infringements are also a concern. Best wishes.
All compliments have been made in the comments ! Thanks for the video... To the question why their invention were never used... french car makers never bet on auto trans, it represented only 0.5-1% of car sales until late 2000's... Just wonder why so many engineers live abroad !
Dear Sir, I appreciate your clear explanation and your nice English presentation. I thank God for giving you a nice brain and power to help the world to understand this kind of lessons to students like me, Thanks you Teacher..God bless...
ZF 8HP XX; that's the ZF model number format. The last two numbers, shown as "XX", is the torque rating for the transmission in DecaNewton-Meters (daNm). That torque range it from 30 to 90 decanewton-meters; 300 Nm to 900 Nm.
Aisin transmission uses compound planetary gear sets. A compound planetary gear set is a planetary gear set that has multiple sun gears or multiple ring gears. One is called the Ravingeaux gear set, which has two sun gears, two planet carriers and they share one common ring gear. One Ravingeaux gear set can provide 4 forward gear ratios and also the neutral and reverse. The Aisin AA80E uses one standard planetary gear, plus one Ravingeaux gear set. When combined together, These two gear sets can provide 6 to 8 forward gear ratios. The AA80E uses two gear sets (strictly speaking there is 3 sets - because the compound set contains 2), and 6 shifting elements - 2 brakes and 4 clutches. Compared to the ZF 8HP, the ZF uses 4 standard planetary gear sets and 5 shifting elements (2 brakes and 3 clutches). With the AA80E at each gear there are 4 clutches/brakes are disengaged will still create drag, because there are fluid between the clutch plates and brake pads and it creates fluid drag forces when the plates/pads on each side rotating at a different speed. Compared to the ZF 8HP, it only has 2 clutch/brake disengaged for each gear, therefore the ZF 8HP will has higher operating efficiency. The ZF8 can also handle 114 more lb.-ft. Torque than the AA80E. The ZF8 provides is more efficient providing higher mpg, shifts faster, is more versatile, and less complicated. don't get me wrong the AA80E is a great 8 speed. It just hasn't been around as long as the ZF8 and is behind a little. Give them some time to improve on it.
Seems like a much more intelligent use of the clutches on this Aisin 8spd over the almost absurdly complex ZF 8spd unit in your other video. Surprising the French was the one who thought of this; we automatically assume Japanese & German engineers are good at doing what they do while Peugeots are about as reliable as FCA products in the long-haul (laughs). However the ratio spread between 3, 4 and 5 are pretty darn close, while the 2-3 shift is quite far. I noticed this in the IS-F and RC350 when going full throttle. I guess this helps rapid passing maneuvers, but I guess due to the limitations of this design makes it impossible to equally space them out, which the ZF 8HP seems to be able to do.
Do you have a video on one of the most horrific transmissions ever engineered by those damn Germans..........namely the 4HP 22 which was installed in a wide variety of vehicles throughout the 1980s/1990s. If you are not familiar with it,it will burn-up the Forward Clutches in Park/Neutral during a routine emission test. ZF's reply then,was never warm-up/idle/rev the engine in Neutral/Park without the vehicle on a lift and allowing the driven wheels to spin............and install a larger pan.
John, I really respect the quality of your work and learn so much.How lucky your students are.I have a question,Hyundai has an 8 speed that is supposedly in house.What type is it?Is it an Aisin clone? thanks
That is so fascinating!!! 8 Speeds from a 6 Speed Gearset. Efficient! ..... But didn't Ford do very similar in the 90's, changing Valve Body timing on the A4LD, to make the 5R55??
I'm just a automotive electrical tech but I'm finding your presentations VERY informative. One question though. The front planetary achieving a 1.8 reduction by driving the planetary carrier must have something special happening inside otherwise my understanding is it would be an overdrive. Is it a compound planetary of some sort? The video shows clearly it is a reduction, I'm just curious how. Thank again for the amazing teaching.
+Philip Housel Hi, the front planetary is just a simple gear set, but it is used differently than other transmissions with simple gear sets. The front planetary is only there to provide two input speeds (at the same time) to the Ravigneaux gear set. Until this transmission, a Ravigneaux only had one input speed. The two speeds are used individually or simultaneously depending upon the Ravigneaux gear ratio desired. It is an ingenious design. Thanks for watching!
+WeberAuto thanks for a quick reply. I've been thinking through and researching various planetary gearsets most of the morning. I suspect, upon closer inspection you might discover there's a double planetary carrier in that otherwise simple gearset. again, thank you for the hands on demonstrations. I am very intrigued by how the magic works inside automatic transmissions.
+Philip Housel Hi, you are correct, the input gear set does have double planet gears, but all that does is reverse the direction of the ring gear so that the sun and ring turn the same direction to drive the Ravigneaux gear set. The double pinions do not have any affect on the gear ratio of the front gear set. Good observation. Have a great day!
I don't know whether I missed it but what is the advantage of a 6 speed transmission let alone an 8? I had and older model Camry with 4 speed and I was happy with it. I now have a 2009 Camry which has 6 speeds. I hate it. It seems to always to be shifting as I drive around town. If I am going up a mild overpass it kicks down unnecessarily (in my opinion) and the engine rpms go up. I live in South Florida which is virtually flat yet the shifting seems to never cease with the engine revving up in between shifts. Anyhow, thanks for sharing your knowledge.
+tommie293 Hi, the advantage of more gears in a transmission today is to keep the engine rpm in a small window where the efficiency, power and emissions are at their best. This gives the driver the illusion of high power and delivers good fuel economy at the same time. Thanks for watching!
I have a 2007 Lexus GS460 8 speed Auto with 76k on the clock. I have notice after being parked on steep hills, when the gearbox is cold, it slips in reverse. U-turning at the same time in drive it does the same. Once the car is moving everything seems to be ok. This is very disconcerting. I can not help but think damage is being done.is there any way to fix this? BTW this gear box oil is changed regularly.
Chances are the damage is done. I believe there is a software update for the transmission controller that may help. The B2 brake (Reverse) and the F1 roller clutch (first) seem to be the weak points in the transmission. Best wishes
Great video! How much power do you think this 8 speed can hold? Also when someone has a built transmission what have they upgraded, especially in the case of this 8 speed? Thanks!
WeberAuto Interesting Thanks! Also one more thing which transmission do you think is more advanced and capable of holding more power this or the ZF 8 speed? Also do you think the new GM/Ford 10 speed will make these 8 speeds obsolete or is 10 just too many?
John love watching your videos. we are currently building the new GM 8speed transmisions 8L45 and 8L90. We just finished the training power flow for that one. i notice the TH400 geartrain holder you use has a spcer inside where did you gte it or have it made?As a 15 year ford technition and now in the remanufacture transmission busniess i can not get enough of transmission and 10 speed gm is right around the corner.Thanks, Terry
+Terrence Trend Hi, thanks. The spacer was part of the TH400 and 4L80E required tools. It is Kent-Moore part number J-21364-A. I love the spacer, I use it with almost every transmission I teach because it keeps things centered in the J-6116-01 holding fixture. Thanks for watching.
Congratulations! I watched it several times walking my dog, so now even he could easy explain the power flowin AA80E transmission😊 I just have two remarks: The front planetary gear set is not a simple one. If that was the case having fixed sun gear and the planet carrier as an input the gear ratio would give an overdrive. Based on the Willis formula the theoretically possible ratio range is form 0.5 to 1.0. Apparently, it is not the case as your video shows at 35:00. It is because the pinion gears/planets that are “rolling” on the fixed sun do not contact the ring gear teeth, but rather turn the outer set of pinion gears. The outer pinions propel the ring gear. From what I’ve found on the internet the front sun gear has 38 teeth, the inner pinions 16, the outer pinions 19 and the ring gear 82. If it was a simple planetary gear set, the ration would be (82+38)/82=1.46. I haven’t done the math yet for the actual design, but I’m sure that’s what gives the reduction. The fourth gear, you give a credit for the ingenuity of the design, takes advantage of splitting the torque and letting it go by two paths. It is easy to understand again by looking at the Willis formula: nr*zr = nc*(zr+zs)-zs*ns. On the one hand you are turning the carrier (nc) but on the other hand you subtract the sun motion (ns). I’m sure you know it, but for the sake of clarity it might be helpful for others. I understand that the aim of your videos is to show how the actual stuff works, but sometimes adding simple math helps.
what would be the base-standard Dodge ½-ton SWB model current which would use this or what model to look for and what to spec for getting away from light-weight manual in my C1500 & the plastic-clutch?
pro guru very nice presentation:Question for you if you would like to answer.8L90E works great except @ WOT the top of the 1-2 shift feels binding not a clean shift.Its boosted custom tuned,to me its like release and apply timing is off.thank you
Professor Kelly, would you have a comment on whether the 8 speed Aisin would have better or worse longevity than the previous 6 speed used in Toyota/Lexus vehicles?
Thanks. I have an older LS430 with the 5 speed and it has over 370K on it with only a couple of fluid changes. That Aisin trans is so good it seems like it will outlast the motor in this car.
This is really interesting. It seems, though, that it's kind of setup in a way that they can boast an 8 speed Trans without much advantage. I mean 3 gears are within a .5 ratio of each other. I don't see how there could be much advantage to that.
OK so that makes sense because earlier in the video you stated that third gear is one to one but it makes sense now that the other three years it’s actually at sixth gear is a one to one for the whole transmission?
professor, why do some ls460 rwd transmissions whine at low speeds and stop whinning around 40 mph. i notice the whinning stops appox 40 mph and there is a gear chage evidenced by a drop in rpm. any ideas how one can remedy this. lexus has a tsb concerning the with a new isolator and mount for mostly 2013 - 2015 production cars but it does not remedy the whine . my concern is longevity of the transmission. thank you for your advice and video time. john aycock naples fl. 2013.ls460 45,000.miles
+WeberAuto Basically a Borg Warner based design from what I recall. Built specifically for Ford Australia and later in the companies life (before DSI was bought out by Cherry - chinese company) they where installing them in Ssang Yong (Korean) and Mahindra (Indian) they where developing a 6speed RWD based on the same casing and internals with another addition to the ravigneux gear train and also a 6speed FWD and a 7speed RWD. I was a draftsman there briefly.
@@WeberAuto You're welcome. For better clarification(more detail), the latest CTS-V runs the 640hp supercharged 6.2L V8 with the GM 8L90 8 Speed auto. The CTS VSPORT is equipped with a 420hp twin turbo 3.6L V6 and the subject Aisin 8 speed auto.
I thourghly enjoy Ur, presentations which are some of the most informative material I have witnessed since I have been rebuilding transmissions, My question is of a personal nature, I have watched videos with U not in Ur chair, would like to know what put U in it
Great vid sir, I enjoy every bit of the info!!! Can you kindly link me to a part number for the tool to check the oil on tht family transmission (AA81) plz. Thank you again
I have not studied the ZF 6HP in detail yet, but I can tell you the 8-speed Aisin is unique in it's design. It is almost like a Dual Clutch Transmission (DCT) where it has two different input shaft speeds. I will make a video on the 6HP later this year. Thanks for your feedback.
There are several potential problems, all are internal to the transmission. I recommend checking for Diagnostic Trouble Codes (DTC) and see where they may point you. Best wishes.
Hello, amazing video i must say. Thank you so much for making this. One thing that boggles my mind for a lobg time now, as you said with the 4 speeds that had overdrive in addition to 3 speed simpson. Why did they not utilize the overdrive to create 6 total ratios instead of the 4 ratio they ended up using. Since overdrive unit is independent of the main unit, theoretically you can switch between the 2 speeds of the overdrive to make the overall gear speeds 6. 3 x 2 = 6. why nobody did this?
I think it’s because that shift pattern would involve “double-transition” shifts, where 2 oncoming and 2 off going clutches must be swapped simultaneously under load, instead of just 1 on and 1 off. This type of shift is more difficult to execute smoothly, especially with some of the hydraulic controls that were available during that era. There are no such transmissions in mass production currently, though the Chrysler 62TE 6-speed did do such shifts (you can find technical papers on the 62TE’s double swap shift strategy through SAE journals). The 62TE was actually a 2 speed x 4 speed configuration, but one of the ratios was redundant with another (now down from 8 to 7 speeds), and another pair of ratios were so close that they were effectively the same (down from 7 to 6).
+British_Leyland(Alexscott100) Hi, I do not know the answer to that, there are so many variables depending on what is wrong with the transmission. It could be anywhere from $500 to the cost of a new transmission. Thanks for watching!
The ZF 8HP has a HD version that is used with the Dodge Hellcat. The Aisin 8 speed, is not quite as heavy duty. Both work very well for their intended applications.
It seems a higher 1st gear, or lower 2gear would giv better performance, 2nd is close to some 1st gear ratios, it will have lots of rpm drop when it shifts to 2nd. But then tight from then on out. Keeping the engine rpm up after shifts. Just imagine this with a 4.56 rear gear. This tbi g would be geared like a clock in 1st !!! This should be great with a 2.73-3.42 gear, depending on tire size... I'm wanting to swap a 6-8 speed in my 88 firebird!
These video's are a must for everyone that has an more than average interest in automotive mechanics.
I hope they stay online forever, there's nothing like it out there.
Of course when you needed 2 weeks to figure out the inner workings of this transmission, its pretty hefty to fully understand all of its workings in just one hour.
I hope you'll be making videos like this for a long time.
Thank you very much! I plan on making many more.
model AA80E is amazingly quick but also cheap to maintain or even rebuild...AISIN makes amazing parts for Japanese cars.
Thanks for your feedback, I agree!
Autre chose que les européennes (fusibles) cette video est dans mon top 5 classement depuis 20 ans de you tube ,MERCI
Man you put a lot of work and thought in this demonstration-Damn! thank you-JJ
+john james Thank you!
Nice job. I don't feel so bad at backing up and re-watching parts of this, after watching you have to really dig deep to get it right. Masterful, truly amazing. Thanks!
Professor Kelly in 2016 when Land Cruiser moved to 8 speed I didn't understand what was the benefit of the two extra gears. That tiny gear change can improve fuel consumption by 11%, that's indeed mind-blowing. You explained it so clearly which I couldn't find anywhere else. Thanks. :)
Awesome video Mr. Kelly. I just can't imagine the minds of the people who can imagine and create such complex mind blowing pieces of engineering marvel. Thanks again Mr. Kelly for this video.
+Russ Dubble U Thank you very much!
I just recently purchased an ISF with this transmission I went up to see my parents they live up in a mountainous area near Tahoe at 75 I’m turning about 1800 to 2000 RPM returning about 26 miles a gallon out of a 5 L V8 with this transmission!
Wow. What a resource. It helps my research so much, I owe mr. Kelly alot. He really deserves that professor title.
just awesome, John. Thanks for providing your knowledge to those of us who appreciate this information.
+Guy Desrochers Thank you! I appreciate the nice comments!
Hi John, excellent description of this Aisin Transmission. I can vouch for the fact this Transmission is also used in the VW Touareg as well. Keep up the Good Work. Garry from Australia
Thank you!
That Aisin 8sp reminds me about tractor transmission, where they do fun things with torque splits a lot. They have main shafts and they have few secondary shafts that use torque in the other ways to make new gears. I've read about some prototypes of mechanical-electric transmission hybrids, where electric motors are used for driving those secondary shafts to simulate CVT ratios.
Thank you for your channel! I'll dig it up. I'd like to invent some usable CVTs for high torque/high speed applications..
Awesome feedback, thank you!
Professor Kelly, Thanks for the demo!
Thank you
I am blown away by your way of explaining. It all makes sense. Thank you for all the information.
Well done and excellent education on the system workings of the 3 systems .The components look stronger than expected. Whe i noticed the time on your computer i realized why the shop was so quiet thanks for staying late to do this can't believe its 5years old !,
Thank you very much
Mr. Kelly. Thank you for this awesome explanation and the effort you put into it. I learned a lot from your descriptions and you clarified some doubts I had about the Lepelletier design.. Regards,
Thanks once again John, another gem from your training school.
+celtichongy Thank you!
I had no real idea of how complex and interesting transmissions are. Thanks.
Brilliant video as always, John.
I've learned so much from your excellent explanations and demos.
Interesting to note: the 2016 BMW X1 model will have the 8spd steptronic AISIN transmission. This is their FWD biased architecture that has Mini roots (platform).
Keep up the fantastic videos!
+Mario Dalla Riva Thank you very much! I did not know about the BMW using the 8-speed Aisin. Cool stuff!
The mercedes benz 722.4 and I think the 722.5 also uses a ravigneaux planetary gearset. It was fitted in vehicles in the late 70s up to mid 90s
It´s a very interesting transmission to look at
just b ought a CTS Vsport and have been trying to learn how the transmission works, this video was gold, thanks!
That's why I was watching as well
Regarding your comment about Ravigneaux gearset, the GM "Hydra-matic" 4L30E has a Ravigneaux gearset, the planetary carrier is the output drive to the prop. However it does only uses 3 speeds from the gearset, the 4th speed is an overdrive and is attached between the torque convertor and the main casing. This transmission was used circa 1992 to 1999, although probably not in US models, it was used in European models in the Vauxhall/Opel stable. Interestingly this transmission was made in France for GM.
Thanks for the feedback!
I just got through explaining everything you have explained in your video to my wife and she understood every single word just before she dropped off to sleep. Just kidding of course.... I have a Chrysler 300c with an 8 speed transmission. It's amazing how so many inner and outer gears can be so accurately machined so they all fit perfectly together. The tolerances have to be amazing and the machines that make the gears. Now I have a little idea as to what a complicated mechanism is moving my car smoothly down the road.
LOL! Thank you!
Holy shit, it took you two weeks to figure out how it works? I wonder how many weeks it took those 3 guys to figure out how to get 2 more gears out of the same set of gears. I can't comprehend the level of ingenuity.
Ken Chen I agree! Thanks for watching!
Wonderful. Very well done. It's a pleasure to listen to you while you share your experience and knowledge. Mike
Thanks for watching
Cool, John. I see that the Ravigneaux works the same way as the Borg Warner / Fordomatic from 1950/51 with the only major difference being those old sets were 3 speed, they did not have the "drive carrier / hold large sun" overdrive gear. The Ravigneaux 4 speed drives the carrier and small sun for 3rd gear, the BW/Fordomatic drove the small sun and large sun, the effect in both cases is to lock the train together giving a 1:1 ratio. I see how the 6 speed Lapelletier is a simple adaptation of the 4 speed Ravigneaux with the additional planetary set in series. Now I see how the Aisin is an adaptation of that Lapelletier. Thanks!
Thanks for your feedback!
Dear WeberAuto,
Thank you for what I consider the best video on youtube explaining the history, progression, and engineering related to the automatic transmission.
You must be a great professor at WSU as your presentation is detailed and readily understood by most users interested in gearing and transmission technology.
I found the detail on the Aisin AA80E to be very informative and also made me think about it competition: GM 8L90E and ZFHP.
The Aisin uses 3 planetary gear sets to achieve 8-ratios while GM and ZF use four.
In addition to my mechanical background, I am also a computer nerd and use binary computations all the time. To me, it seems logical that an 8spd Aisin can be produced using 3-inline gear sets: 2x2x2=8 (2 x 4spds)
That being said, why does GM or ZF not use four gear-sets to produce an 16spd trans?.....2x2x2x2=16
Could be possible redundancy in gear rations or OD of ring gear being too large for application and achieve even spacing?
Any thoughts? Or am I off-base in believing that 4 planetary gear sets can achieve 16spds?
PS: Heavy duty trucks have been using the x2 multiplier since the 80's or earlier (even Corvette offered a 4+3 manual)
Interested in your professional comments.
Thank you,
Alan - Automotive Engineer
LSmiata Thanks for watching and for your nice comments. Each planetary gear set is actually capable of delivering: two under-drive ratios, direct-drive, two over-drive ratios, and two reverse ratios. The more gear sets you use the more expensive, heavy, and complex the transmission becomes. I know that cost and weight are the two main factors in design. Patent infringements are also a concern. Best wishes.
Great video as usual Mr. Kelly. Ford used a Ravigneaux gear set in the AOD/4R70W transmissions for 4 speeds.
Amazing demo, thanks professor Kelly!
Glad you liked it!
All compliments have been made in the comments ! Thanks for the video... To the question why their invention were never used... french car makers never bet on auto trans, it represented only 0.5-1% of car sales until late 2000's... Just wonder why so many engineers live abroad !
Thank you!
Your videos are just awesome! Subscribed!! I watched the full 1+ hour but felt as a 5min video, time flew.
rodstartube . pd: 41:22 a ghostbuster in action?
rodstartube Thank You!
amazing demonstration of a complex design. Thank you
Glad you liked it!
LOL, I had always assumed that transmissions were operated by magic and sorcery. . . You've successfully converted me. . . Well done sir.
+New Energy Thank you very much! They are amazing pieces of hardware!
Dear Sir, I appreciate your clear explanation and your nice English presentation. I thank God for giving you a nice brain and power to help the world to understand this kind of lessons to students like me, Thanks you Teacher..God bless...
ZF 8HP XX; that's the ZF model number format.
The last two numbers, shown as "XX", is the torque rating for the transmission in DecaNewton-Meters (daNm). That torque range it from 30 to 90 decanewton-meters; 300 Nm to 900 Nm.
Thanks for the information
Came across this while researching the transmission in our new family car a 2019 vw atlas
Aisin transmission uses compound planetary gear sets. A compound planetary gear set is a planetary gear set that has multiple sun gears or multiple ring gears. One is called the Ravingeaux gear set, which has two sun gears, two planet carriers and they share one common ring gear.
One Ravingeaux gear set can provide 4 forward gear ratios and also the neutral and reverse. The Aisin AA80E uses one standard planetary gear, plus one Ravingeaux gear set. When combined together, These two gear sets can provide 6 to 8 forward gear ratios. The AA80E uses two gear sets (strictly speaking there is 3 sets - because the compound set contains 2), and 6 shifting elements - 2 brakes and 4 clutches. Compared to the ZF 8HP, the ZF uses 4 standard planetary gear sets and 5 shifting elements (2 brakes and 3 clutches). With the AA80E at each gear there are 4 clutches/brakes are disengaged will still create drag, because there are fluid between the clutch plates and brake pads and it creates fluid drag forces when the plates/pads on each side rotating at a different speed. Compared to the ZF 8HP, it only has 2 clutch/brake disengaged for each gear, therefore the ZF 8HP will has higher operating efficiency. The ZF8 can also handle 114 more lb.-ft. Torque than the AA80E. The ZF8 provides is more efficient providing higher mpg, shifts faster, is more versatile, and less complicated. don't get me wrong the AA80E is a great 8 speed. It just hasn't been around as long as the ZF8 and is behind a little. Give them some time to improve on it.
Thanks for your feedback. The ZF 8HP is a better transmission. Even the latest Aisin AE80E 8-speed is having troubles with higher torque loads.
I am fascinated by epicyclic gearboxes.
Seems like a much more intelligent use of the clutches on this Aisin 8spd over the almost absurdly complex ZF 8spd unit in your other video. Surprising the French was the one who thought of this; we automatically assume Japanese & German engineers are good at doing what they do while Peugeots are about as reliable as FCA products in the long-haul (laughs).
However the ratio spread between 3, 4 and 5 are pretty darn close, while the 2-3 shift is quite far. I noticed this in the IS-F and RC350 when going full throttle. I guess this helps rapid passing maneuvers, but I guess due to the limitations of this design makes it impossible to equally space them out, which the ZF 8HP seems to be able to do.
Thanks for your feedback! good points.
thanks john for your detail explaination, greeting from China :)
+minkun zhu Thank you!
yes the rauigneaux was used by ford in about 1980 in the AOD transmission.
+Terrence Trend Thank you for the feedback!
SolidCopy1, The Hellcat uses the ZF 8HP 8-Speed automatic transmission I mentioned in this video. Thanks for watching.
Do you have a video on one of the most horrific transmissions ever engineered by those damn Germans..........namely the 4HP 22 which was installed in a wide variety of vehicles throughout the 1980s/1990s.
If you are not familiar with it,it will burn-up the Forward Clutches in Park/Neutral during a routine emission test. ZF's reply then,was never warm-up/idle/rev the engine in Neutral/Park without the vehicle on a lift and allowing the driven wheels to spin............and install a larger pan.
John,
I really respect the quality of your work and learn so much.How lucky your students are.I have a question,Hyundai has an 8 speed that is supposedly in house.What type is it?Is it an Aisin clone? thanks
The hydro-matic was a 4 speed. I had one that came out of a 53 Cady, i had it in a 32 Ply.
Great Video , thumb up for Ypu Mr. Kelly . Hello from Italy
Thank you!
great great video.explanation is very clear..thanks for this video sir.from philipines.....
Great & informative video Mr. Kelly! How often should I change the fluid in my AA80E? I was planning on doing a simple drain & refill at 60,000 miles.
I would do it at 60,000 miles, but technically, it is sealed for life and never needs changing (I am laughing). Best wishes!
That is so fascinating!!! 8 Speeds from a 6 Speed Gearset. Efficient!
..... But didn't Ford do very similar in the 90's, changing Valve Body timing on the A4LD, to make the 5R55??
"Wee-Burr Auto TH-cam channel"
Have I been saying this wrong the whole time? :D
Great work! Fascinating mechanics.
Thank you!
The 6L80e valve body was made by AISIN, properly the whole transmission.
8L90 brought to you by AISIN..Why not :)
Thanks for the demo!
+Camaro Rick Thank you!
I'm just a automotive electrical tech but I'm finding your presentations VERY informative. One question though. The front planetary achieving a 1.8 reduction by driving the planetary carrier must have something special happening inside otherwise my understanding is it would be an overdrive. Is it a compound planetary of some sort? The video shows clearly it is a reduction, I'm just curious how. Thank again for the amazing teaching.
+Philip Housel Hi, the front planetary is just a simple gear set, but it is used differently than other transmissions with simple gear sets. The front planetary is only there to provide two input speeds (at the same time) to the Ravigneaux gear set. Until this transmission, a Ravigneaux only had one input speed. The two speeds are used individually or simultaneously depending upon the Ravigneaux gear ratio desired. It is an ingenious design. Thanks for watching!
+WeberAuto thanks for a quick reply. I've been thinking through and researching various planetary gearsets most of the morning. I suspect, upon closer inspection you might discover there's a double planetary carrier in that otherwise simple gearset. again, thank you for the hands on demonstrations. I am very intrigued by how the magic works inside automatic transmissions.
+Philip Housel patentimages.storage.googleapis.com/US8251860B2/US08251860-20120828-D00000.png
+Philip Housel Hi, you are correct, the input gear set does have double planet gears, but all that does is reverse the direction of the ring gear so that the sun and ring turn the same direction to drive the Ravigneaux gear set. The double pinions do not have any affect on the gear ratio of the front gear set. Good observation. Have a great day!
I don't know whether I missed it but what is the advantage of a 6 speed transmission let alone an 8? I had and older model Camry with 4 speed and I was happy with it. I now have a 2009 Camry which has 6 speeds. I hate it. It seems to always to be shifting as I drive around town. If I am going up a mild overpass it kicks down unnecessarily (in my opinion) and the engine rpms go up. I live in South Florida which is virtually flat yet the shifting seems to never cease with the engine revving up in between shifts. Anyhow, thanks for sharing your knowledge.
+tommie293 Hi, the advantage of more gears in a transmission today is to keep the engine rpm in a small window where the efficiency, power and emissions are at their best. This gives the driver the illusion of high power and delivers good fuel economy at the same time. Thanks for watching!
I have a 2007 Lexus GS460 8 speed Auto with 76k on the clock. I have notice after being parked on steep hills, when the gearbox is cold, it slips in reverse. U-turning at the same time in drive it does the same. Once the car is moving everything seems to be ok. This is very disconcerting. I can not help but think damage is being done.is there any way to fix this? BTW this gear box oil is changed regularly.
Chances are the damage is done. I believe there is a software update for the transmission controller that may help. The B2 brake (Reverse) and the F1 roller clutch (first) seem to be the weak points in the transmission. Best wishes
Great video! How much power do you think this 8 speed can hold? Also when someone has a built transmission what have they upgraded, especially in the case of this 8 speed? Thanks!
Thank you! The model in this video was not intended for high torque and horsepower. Newer versions of it are strengthened more.
WeberAuto Interesting Thanks! Also one more thing which transmission do you think is more advanced and capable of holding more power this or the ZF 8 speed? Also do you think the new GM/Ford 10 speed will make these 8 speeds obsolete or is 10 just too many?
Earning Learning engine Competency! Thanks, sir
Great video, thanx
Thank you!
John love watching your videos. we are currently building the new GM 8speed transmisions 8L45 and 8L90. We just finished the training power flow for that one. i notice the TH400 geartrain holder you use has a spcer inside where did you gte it or have it made?As a 15 year ford technition and now in the remanufacture transmission busniess i can not get enough of transmission and 10 speed gm is right around the corner.Thanks, Terry
+Terrence Trend Hi, thanks. The spacer was part of the TH400 and 4L80E required tools. It is Kent-Moore part number J-21364-A. I love the spacer, I use it with almost every transmission I teach because it keeps things centered in the J-6116-01 holding fixture. Thanks for watching.
Congratulations! I watched it several times walking my dog, so now even he could easy explain the power flowin AA80E transmission😊 I just have two remarks:
The front planetary gear set is not a simple one. If that was the case having fixed sun gear and the planet carrier as an input the gear ratio would give an overdrive. Based on the Willis formula the theoretically possible ratio range is form 0.5 to 1.0. Apparently, it is not the case as your video shows at 35:00. It is because the pinion gears/planets that are “rolling” on the fixed sun do not contact the ring gear teeth, but rather turn the outer set of pinion gears. The outer pinions propel the ring gear. From what I’ve found on the internet the front sun gear has 38 teeth, the inner pinions 16, the outer pinions 19 and the ring gear 82. If it was a simple planetary gear set, the ration would be (82+38)/82=1.46. I haven’t done the math yet for the actual design, but I’m sure that’s what gives the reduction.
The fourth gear, you give a credit for the ingenuity of the design, takes advantage of splitting the torque and letting it go by two paths. It is easy to understand again by looking at the Willis formula: nr*zr = nc*(zr+zs)-zs*ns. On the one hand you are turning the carrier (nc) but on the other hand you subtract the sun motion (ns). I’m sure you know it, but for the sake of clarity it might be helpful for others. I understand that the aim of your videos is to show how the actual stuff works, but sometimes adding simple math helps.
what would be the base-standard Dodge ½-ton SWB model current which would use this or what model to look for and what to spec for getting away from light-weight manual in my C1500 & the plastic-clutch?
Díky!
Thank you very much Jaroslav! Your gift is much appreciated.
@@WeberAuto You're welcome.
The explanation of developmental history was great.
great video, great presentation Thank you
ZF 8 speed was available in 2010 on 5-series.
That is true. The Aisin AA80E was available in Lexus 2008
Arnis Tarassu
pro guru very nice presentation:Question for you if you would like to answer.8L90E works great except @ WOT the top of the 1-2 shift feels binding not a clean shift.Its boosted custom tuned,to me its like release and apply timing is off.thank you
Professor Kelly, would you have a comment on whether the 8 speed Aisin would have better or worse longevity than the previous 6 speed used in Toyota/Lexus vehicles?
I personally think the 6 speed is more heavy duty and can handle heavy loads better. Other than that, the 8-speed is great
Thanks. I have an older LS430 with the 5 speed and it has over 370K on it with only a couple of fluid changes. That Aisin trans is so good it seems like it will outlast the motor in this car.
it was really good explaination. A lot better than my Professor. Mr.Kelly, why dont you start taking lectures in University?
i just googled and found out that you are professor. Is there any possibility that you might take few lectures in Germany?
Thank you!
I wish I could, but I am confined to a wheelchair now and it is too difficult to travel.
This is really interesting. It seems, though, that it's kind of setup in a way that they can boast an 8 speed Trans without much advantage. I mean 3 gears are within a .5 ratio of each other. I don't see how there could be much advantage to that.
thanks professor, very very useful video.👍👍👍
thats why the lexus LS is so silky smooth
Thanks for your feedback
dude, that it amazing..... great info
Thanks!
Great Video, keep making them please :)
NuclearCowboy Thank you! Many more to come.
OK so that makes sense because earlier in the video you stated that third gear is one to one but it makes sense now that the other three years it’s actually at sixth gear is a one to one for the whole transmission?
Thanks for your feedback
professor, why do some ls460 rwd transmissions whine at low speeds and stop whinning around 40 mph. i notice the whinning stops appox 40 mph and there is a gear chage evidenced by a drop in rpm. any ideas how one can remedy this. lexus has a tsb concerning the with a new isolator and mount for mostly 2013 - 2015 production cars but it does not remedy the whine . my concern is longevity of the transmission. thank you for your advice and video time. john aycock naples fl. 2013.ls460 45,000.miles
In the early 50s GM had the Hydro-matic automatic transmission. Did it use the Monroe gear set?
If I’m correct the torque converter can lock up at certain intervals during different gears?
Yes
Btr or ion or DSI (same company) made a four speed using the ravigneux gear set. Australian.
boganindustries Thank you! I did not know that.
+WeberAuto Basically a Borg Warner based design from what I recall. Built specifically for Ford Australia and later in the companies life (before DSI was bought out by Cherry - chinese company) they where installing them in Ssang Yong (Korean) and Mahindra (Indian) they where developing a 6speed RWD based on the same casing and internals with another addition to the ravigneux gear train and also a 6speed FWD and a 7speed RWD. I was a draftsman there briefly.
Thanks Im a rebuilder mechanic transmission and the info its amaizing . If you have one of gtr and pdk apreciate
Cadillac CTS VSport uses this Aisin, NOT the CTS-V. Those are 2 different vehicles/drivetrains.
Thanks for your feedback!
@@WeberAuto You're welcome. For better clarification(more detail), the latest CTS-V runs the 640hp supercharged 6.2L V8 with the GM 8L90 8 Speed auto.
The CTS VSPORT is equipped with a 420hp twin turbo 3.6L V6 and the subject Aisin 8 speed auto.
Hi have you done ford's new 10 speed?
No, but I will as soon as I can get one. Thanks!
In your opinion Sir, which is the better 8 speed auto?
Tx for a very informative video! (The French do not get the credit they deserve in engineering! )
+Don G. Thank you very much! They do deserve the credit.
hi jhon thanks a lot for your videos i just start and i want to learn would you explain why the final drive need a reduction gear.
+Marek Wijas Hi, the final drive gear reduction also multiplies engine torque. it allows the vehicle to accelerate rapidly.
+WeberAuto thanks
I thourghly enjoy Ur, presentations which are some of the most informative material I have witnessed since I have been rebuilding transmissions,
My question is of a personal nature, I have watched videos with U not in Ur chair, would like to know what put U in it
Thank you very much. Muscular dystrophy
great video. my head would explode.
Great vid sir, I enjoy every bit of the info!!! Can you kindly link me to a part number for the tool to check the oil on tht family transmission (AA81) plz. Thank you again
Thank you!. There is no tool, you just check it at the proper fluid temperature. Best wishes!
WeberAuto thanks for responding hav a great day
ZF 6HP transmission also is this design, which the difference between 6hp and ASIN 6 speed or 8 speed transmission
I have not studied the ZF 6HP in detail yet, but I can tell you the 8-speed Aisin is unique in it's design. It is almost like a Dual Clutch Transmission (DCT) where it has two different input shaft speeds. I will make a video on the 6HP later this year. Thanks for your feedback.
compound gear sets= one planet driving another gear set ?
Yes, there are many variations of that. It creates a gear ratio that neither gear set could create on its own. Thanks for your feedback.
thanx so much
Pretty sure it was actually the cts v-sport that used this trans rather than the v, awesome video tho
thank you...
Love the video
Thank you!
So would sixth gear be basically 1:1????
you were born to teach...
You forgot about Chryslers 8 speed RWD torque flight transmission used in the Hellcat.
That's basically a modified version of ZF 8HP
sir, what you think would cause one gear to shift rough then all the others ?
There are several potential problems, all are internal to the transmission. I recommend checking for Diagnostic Trouble Codes (DTC) and see where they may point you. Best wishes.
+WeberAuto it only happen when cold start shifting 3rd gear
Hello, amazing video i must say. Thank you so much for making this. One thing that boggles my mind for a lobg time now, as you said with the 4 speeds that had overdrive in addition to 3 speed simpson. Why did they not utilize the overdrive to create 6 total ratios instead of the 4 ratio they ended up using. Since overdrive unit is independent of the main unit, theoretically you can switch between the 2 speeds of the overdrive to make the overall gear speeds 6. 3 x 2 = 6. why nobody did this?
I think it’s because that shift pattern would involve “double-transition” shifts, where 2 oncoming and 2 off going clutches must be swapped simultaneously under load, instead of just 1 on and 1 off. This type of shift is more difficult to execute smoothly, especially with some of the hydraulic controls that were available during that era.
There are no such transmissions in mass production currently, though the Chrysler 62TE 6-speed did do such shifts (you can find technical papers on the 62TE’s double swap shift strategy through SAE journals). The 62TE was actually a 2 speed x 4 speed configuration, but one of the ratios was redundant with another (now down from 8 to 7 speeds), and another pair of ratios were so close that they were effectively the same (down from 7 to 6).
@@pmo5821 thank you so much for your answer , i will read up on that chrysler transmission that you have mentioned
+WeberAuto how much does it typically cost to rebuild a 8-Speed automatic
+British_Leyland(Alexscott100) Hi, I do not know the answer to that, there are so many variables depending on what is wrong with the transmission. It could be anywhere from $500 to the cost of a new transmission. Thanks for watching!
+WeberAuto and how much is the cost of a "new transmission" ??
Replacing the a960e with this in the Toyota 86 would be excellent.
Thanks for your feedback!
ZF 8hp or aisin 8 speed, which one is better.?
The ZF 8HP has a HD version that is used with the Dodge Hellcat. The Aisin 8 speed, is not quite as heavy duty. Both work very well for their intended applications.
It seems a higher 1st gear, or lower 2gear would giv better performance, 2nd is close to some 1st gear ratios, it will have lots of rpm drop when it shifts to 2nd. But then tight from then on out. Keeping the engine rpm up after shifts. Just imagine this with a 4.56 rear gear. This tbi g would be geared like a clock in 1st !!! This should be great with a 2.73-3.42 gear, depending on tire size... I'm wanting to swap a 6-8 speed in my 88 firebird!
Thanks for your feedback