Where did you get that info from? It is not the same transmission just cause it has the number "8" in it. Check my post above.

 

Oh damn. Second time I'm wrong today.

 

This is the 8 speed AWF8F35 for FF applications:


This is the AA80E/AA81E designed for rear drive:



Same number of gears, completely different box.

 

Also nice ninja edit. Beat ya =P

 

Hello guys, I know this is an old thread, however the 8 speed gearbox is still current on our day to day drive
So, without further comments, for those who can lose some time to see how these gearboxes work, watch the video.


For those who don't have patience, just check the 39:15, however it would be a shame not to know the whole history.



Also, extracted from another source, we have the tech explanations and moving parts chart (http://blogs.youwheel.com/2014/04/29...t-aisin-aa80e/)
Aisin AA80E, which is used in the Lexus IS350, GS350, LS460, IS-F and the upcoming RC-F.



Unlike other longitude mounted 8AT such as the ZF 8HP and GM 8L90, the 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. There are different types of them, the one we are interested in 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. By the way, there is a name for such combination: it is called a Lepelletier System.

Therefore 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 (no including an extra one-way clutch which prevents the rear planetary carrier from turning counterclockwise in gear #1).

Compared to the ZF 8HP, the ZF uses 4 standard planetary gear sets and 5 shifting elements (2 brakes and 3 clutches).

The advantage of Lepelletier System is: it is more compact and saves weight (the AA80E weights 95kg, 209 lbs). For your reference, the ZF 6-speed transmission 6HP32 weights around 99kg (218 lbs). But this comes with expense, look at the following AA80E shifting chart, you will see at each gear there are 4 clutches/brakes are disengaged.



Disengaged clutches and brakes 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 Aisin AA80E is rated at 550 Nm torque (406 lb-ft). However the version that Aisin supplies to GM on its Cadillac CTS VSport has higher torque rating, because the CTS VSport engine output torque is 430 lb-ft. The highest trim of ZF 8HP can handle up to 664 lb-ft of torque

At this moment you may have an impression that the Aisin 8AT is inferior to the ZF 8HP, but please remember its first usage is on the 2007 Lexus LS460, the actual design was finalized in 2004; while the first time you see the ZF 8HP (on BMW F01 7-Series) is in late 2008. And also the shifting operation scheme of the Aisin 8AT does provide a better response in some circumstances. For example on highway cruise, if you want to accelerate quickly to pass, you may need the transmission to shift from 8th gear to 5th gear directly, in this situation the Aisin 8AT only need two shifting element to change status, while the ZF 8HP need 4 of them to engage/disengage.



And the AISIN factory statements regarding this gearbox:

TL-80SN

High Torque Capacity RWD 8-Speed Automatic Transmission

• ・Provides both excellent acceleration and low fuel consumption with optimal use of engine torque
• ・Quiet operation and shifting performance worthy of luxury vehicles
• ・Lightweight due to the integrated housing case (converter housing and extension housing)

Torque Capacity(Nm)
583

 

^^ That was an interesting video to watch!! Much better than the accidental "tranny" videos that came up in my usual search (lol)

It amazes me how sophisticated cars have become - we get into them and drive away without giving much thought on the marvel of engineering that went into them....

 

Great information. I've drive the 335/340 and to be honest, it feels like it's much more responsive at highway speeds. It shifts much faster in all situations especially in manual mode. Perhaps additional tuning overcame any theoretical advantages the Aisin has.

 

You got me thinking now, as I've driven a 335 as well, couple years back. And what comes to my mind is this - better tuning for sure. Better tuning which involves a whole range of inputs.

For example, when I got my car, almost 2 years ago, I was like... wtf... From a stop, kept praying for it to go. And, the gear changes were not quite so responsive to my taste, not bad, but not great. That was on the test drive prior to buy it. That was a major downside, as I live in a very heavy traffic city, where you have to kick-off fast to get to your business. So, just before actually buying it, I got a pedal accelerator device that changes the way the acceleration input is fed to the ECU (doesn't matter the brand and type, mind you I live in Europe, but already used it on my previous cars and for me the results were perfect). And after installing it, not that I have *almost* defeated the dreaded lag from a standstill, but also the gearbox started to be more responsive and it's a pleasure to drive both in city and on the highway. To be truthful, I rarely use the Manual Mode now, only on mountain roads where I really want the gearbox to do exactly what I want, no stupid upshifts while climbing and such.

So, by modifying just the acceleration input the gearbox is a lot more responsive now, and fun to drive. I would say it's getting closer to the BMW gearbox, but still behind And once again, think of the tuning the BMW did, I'm pretty sure it involves more that just acceleration...

Anyway, if there are people still complaining about this gearbox with stock cars, trust me, you lose a lot, actually you'll be missing the fun until you install a good reputable accelerator booster. Just my opinion.
LE Of course, I am not talking about complete tuning like ECU remap, and transmission computer retune... Those will definitely be better options, but more invasive.