ClubLexus - Lexus Forum Discussion - World's First 8 Speed Automatic Transmission

Guys I ran across this video which is almost 4 years old this April, but I've never seen a video breakdown on our transmission like this guy does it!!

It breaks it down as follows:

Weber State University (WSU) - Automotive Technology Department - Transmission Lab. This episode covers the amazing Aisin 8-Speed Automatic Transmission which is used in the 2016 Toyota Land Cruiser (AE80F), 2007-2016 Lexus rear-wheel drive vehicles (model AA80E) as well as the 2014 -2015 Cadillac CTS-V Sport (model TL-80SN). This is an amazing piece of technology that uses a modified Lepelletier gear set to obtain 8 forward speeds and reverse with just 2 planetary gear sets. Other vehicle manufacturers have developed 8 speed automatic transmissions, but they use four planetary gear sets (GM's 8L90, and the ZF 8HP).

Another quote here from a comment:

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.

^^^^^ The above comment was interesting and provided some facts on the transmission vs the ZF 8HP but his comments at the end don't make sense because the AA80E has been around longer so I don't know what he meant by that comment, but nonetheless it has some comparisons between the two transmissions.

What is interesting also is that our transmission is a combination of patents from 3 guys, 1 French guy from 1949 on the Ravingeaux gear set the 2nd patent from another French guy in 1989 on the Lepelletier gear set to couple one standard planetary gear, plus one Ravingeaux gear set to obtain 6 forward gears, then in 1999 a Japanese guy who worked with Aisin patented a way to squeeze out 2 overdrive gears (7th & 8th gears) with the above patents mentioned and patented the 8 speed design that Lexus used from Asin and put in the 2007 LS 460 and eventually made it's way to the ISF and so on and so forth to other models throughout the last decade. It's the only transmission on the market that uses his patent for this 8 speed design.

Video below, grab some coffee and watch this if you want to geek out on the inner workings of our transmission:)