Are our transmissions lazy?
12-23-2019, 12:32 AM
#16
Change was done at 118K, but knowing what I know now, I should have done it much earlier - and I'll be doing it on a more regular basis moving forward. I had the fluid tested at Blackstone, and they recommended I run this current fill for about 38K and send them a new sample, so I may just change it at this time as well.
Fluid used was RAVENOL T-WS ATF
Fluid used was RAVENOL T-WS ATF
12-23-2019, 10:11 AM
#17
Im very aware that there are different versions of the 8hp* but the only one that is rated for more than the aisins 850Nm is the 8hp90 and the 8hp95 which are really only used in bentleys, rolls royce, aston martins, and anything dodge makes with a hellcat motor.
Regarding fuel efficiency i was referring mostly to gas motors. Obviously the powertrain could have a lot to do with it, but considering a 958 cayenne turbo is rated for 22 highway mpg and a comparable x5m is rated for 19, i figured trans and gearing could have something to do with it. Comparing diesels is tough too because fuel efficiency is within 1 mpg (cayenne at 22/28 vs x5d at 23/29)and 0-60 is about a second difference at 6.0 to 7.0 from what ive seen, which isnt surprising because the 8hp should yield faster acceleration.
One thing you forgot in you "only possible advantage" statement was that because the aisin is a truck transmission, with a transfer case and such, it allows for center and rear locking differentials, which as far as I know is not possible with an 8hp.
Regarding fuel efficiency i was referring mostly to gas motors. Obviously the powertrain could have a lot to do with it, but considering a 958 cayenne turbo is rated for 22 highway mpg and a comparable x5m is rated for 19, i figured trans and gearing could have something to do with it. Comparing diesels is tough too because fuel efficiency is within 1 mpg (cayenne at 22/28 vs x5d at 23/29)and 0-60 is about a second difference at 6.0 to 7.0 from what ive seen, which isnt surprising because the 8hp should yield faster acceleration.
One thing you forgot in you "only possible advantage" statement was that because the aisin is a truck transmission, with a transfer case and such, it allows for center and rear locking differentials, which as far as I know is not possible with an 8hp.
For transfer case, how do you think power is distributed to all wheels on x5 and Cayenne gen3 if not through a transfer case?
Last edited by RomSL; 12-23-2019 at 10:26 AM.
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Leadfoot_mf (04-20-2020)
04-19-2020, 09:20 PM
#19
Instructor
Change was done at 118K, but knowing what I know now, I should have done it much earlier - and I'll be doing it on a more regular basis moving forward. I had the fluid tested at Blackstone, and they recommended I run this current fill for about 38K and send them a new sample, so I may just change it at this time as well.
Fluid used was RAVENOL T-WS ATF
Fluid used was RAVENOL T-WS ATF
Good to hear it makes a big difference. I'm hopeful. Love the beast but the shifting is the worst I've ever had in an auto, particularly down 4->3 and 3->2.
Ken
04-19-2020, 09:40 PM
#20
First time hearing sluggish performance on the 8 speed, I thought they shifted pretty well, at least during my limited drives. Changing ATF before 100k is a good thing To do though
04-20-2020, 02:36 PM
#22
I did my own change. It's not too difficult, but there are a lot of steps, and to make sure you have it correctly filled there is a bit of a process to follow, but overall it's very doable if you have the time. Now that I know how to do it, I'll be doing it again down the road.
I also went ahead and changed the fluid in the transfer case and both diffs a week after the transmission was done, and that made a difference as well, but more on cornering or lateral maneuvering, and not nearly the change the transmission made.
The vehicle is also a ton quieter while driving, which was also surprising to me... I'll be staying on top of those fluids from now on.
I also went ahead and changed the fluid in the transfer case and both diffs a week after the transmission was done, and that made a difference as well, but more on cornering or lateral maneuvering, and not nearly the change the transmission made.
The vehicle is also a ton quieter while driving, which was also surprising to me... I'll be staying on top of those fluids from now on.
04-21-2020, 10:06 AM
#24
Rennlist Member
FWIW, even car and driver noticed the sluggish transmission when they tested the 958.2: "the autobox would occasionally deliver an upshift that felt as if it were executed by an old GM Turbo Hydra-Matic 400 with a shift kit". link
The best part of a recent 9Y0 loaner cayenne was the transmission, didn't care much for the 3.0T engine.
The best part of a recent 9Y0 loaner cayenne was the transmission, didn't care much for the 3.0T engine.
04-21-2020, 11:27 AM
#25
Instructor
Change was done at 118K, but knowing what I know now, I should have done it much earlier - and I'll be doing it on a more regular basis moving forward. I had the fluid tested at Blackstone, and they recommended I run this current fill for about 38K and send them a new sample, so I may just change it at this time as well.
Fluid used was RAVENOL T-WS ATF
Fluid used was RAVENOL T-WS ATF
12-09-2023, 10:00 PM
#27
Rennlist Member
reviving this thread, i recently drove a 2014 cayenne GTS, and got back in my 2013 S and thought my transmission is much lazier than the 2014 GTS. The thing is, i just did the transmission fluid flush!! Im thinking of buying a TCM (transmission control module) from a 2014 GTS to see if that gives me the quicker shifts. What do you guys think?
12-09-2023, 10:44 PM
#28
Rennlist Member
Thread Starter
I remember doing a tcu tune on my 957 and it didn’t make much of a difference. Can’t remember the vendor. The biggest change was accomplished by turning PSM off.
fast forward I ended up getting a 958 and then got an X5M, which is the best suv I have ever owned. It has different settings for transmission, suspension, and engine all independently which allows for many different personalities.
with that being said I’m trading it for a GLE 63s in the next week or so.
fast forward I ended up getting a 958 and then got an X5M, which is the best suv I have ever owned. It has different settings for transmission, suspension, and engine all independently which allows for many different personalities.
with that being said I’m trading it for a GLE 63s in the next week or so.
12-10-2023, 03:08 AM
#29
RL Community Team
Rennlist Member
Rennlist Member
reviving this thread, i recently drove a 2014 cayenne GTS, and got back in my 2013 S and thought my transmission is much lazier than the 2014 GTS. The thing is, i just did the transmission fluid flush!! Im thinking of buying a TCM (transmission control module) from a 2014 GTS to see if that gives me the quicker shifts. What do you guys think?
12-10-2023, 05:17 AM
#30
Rennlist Member