Auto slipping
Thread Starter
Burning Brakes
Joined: Jan 2009
Posts: 961
Likes: 0
From: Woodbridge, VA.
Auto slipping
Hey Everyone !! Had a blast at SITM !! Met a great bunch of folks from all over and thought I might bounce something off the 'rogerbox' crew. I Have a 1988 S4 Auto..pretty stock Indischrot red...Virginia tag 928 S4S I probably talked to few of ya. Anyhow, when I bought the car, I tried to drive from Minneapolis to D.C. and after the bumpy roads in Wisconsin, I clogged the trans filter no go..shipped it home and figured out what it was and among alot of other maintenance, changed the trans filter kit...shifted better and better all last season. This year, I went to a High Perfprmance driving PCA event in April and on the way home it would not shift into 4th at all.. Did another trans kit before SITM and it ran great up and down the mountains and most of the way home til half way back up I-81..let it cool down..just fine and just when I got within short distance from home it again would not go into 4th. Now it starts fine and shifts...Note: I do have that slight leak at the Torque Converter window..plug sealed well.. and I know that the TC leaks down at rest..planning a TC seals and TT rebuild this winter/ Any overall thoughts or suggestions in the short term will be appreciated Thanks, Kevin 
Drifting
Joined: Jun 2006
Posts: 2,708
Likes: 77
From: Indianapolis Area
Tran-X,,, appears to be working for me and I have the exact same problem.
Looking to rebuild in the fall if it can wait.
More here:
https://rennlist.com/forums/928-foru...ion-fluid.html
Looking to rebuild in the fall if it can wait.
More here:
https://rennlist.com/forums/928-foru...ion-fluid.html
Under the Lift
Lifetime Rennlist
Member
Lifetime Rennlist
Member
Joined: Mar 2002
Posts: 18,648
Likes: 52
From: Buckeye, AZ
You say "clogging" the filter and repeated loss of shifting into 4th gear over time even after a trans service. To me this sounds like your clutches could be disintegrating and debris is jamming the 3-4 shift valve. A fluid change and some trans treatment cleans this up and resolves the shift problem for a while, but it returns. I have had a few instances where I lost the downshift into first gear and servicing the tranny fluid and filter resolved it. Mine's been fine for years now, but if it were to come back and not resolve easily, I will pull the tranny and rebuild it. On the other hand, it could just be a problem inside the valve body fixable by getting a rebuilt valve body from Steve Cattaneo.
The traditional way of doing the TT involves tranny removal. Obviously, that would be an excellent time to do a tranny rebuild.
In the short term, your shift issue may be fine for months or even years, like mine. If it returns, I would put in a can of trans cleaner that is intended to be left in as opposed to being used as a flush. If no change in the problem within a day or two, then change the fluid and filter. If no change, it's rebuild time. I'm waiting for something more definitive to happen to my car. Lately, I think my 2-3 shift has gotten sloppier, so it may not be much longer. I've never done anything at all to the tranny other than religious fluid and filter changes every 30K miles.
The traditional way of doing the TT involves tranny removal. Obviously, that would be an excellent time to do a tranny rebuild.
In the short term, your shift issue may be fine for months or even years, like mine. If it returns, I would put in a can of trans cleaner that is intended to be left in as opposed to being used as a flush. If no change in the problem within a day or two, then change the fluid and filter. If no change, it's rebuild time. I'm waiting for something more definitive to happen to my car. Lately, I think my 2-3 shift has gotten sloppier, so it may not be much longer. I've never done anything at all to the tranny other than religious fluid and filter changes every 30K miles.
Thread Starter
Burning Brakes
Joined: Jan 2009
Posts: 961
Likes: 0
From: Woodbridge, VA.
Thanks Auzi and Bill....I seem to be on that same path toward eventual TT rebuild w/ Constantine clamp and larger bearings along with a trans rebuild and seals and possibly a Torque Converter...man that will be some dinars !! I seem to only get these issues after a lot of Highway time. Would really like to add a trans cooler upgrade and temp gauge when I get all this done this coming winter.. Thanks again Kevin By the way Bill...awesome video burnout and 204 k and also a Super charger ?? I think my tranny is not getting anywhere near the workout you give yours !! Oh Yeah...sorry, my 88 S4 has 92,000 mies now
By the way Bill...awesome video burnout and 204 k and also a Super charger ?? I think my tranny is not getting anywhere near the workout you give yours !! Oh Yeah...sorry, my 88 S4 has 92,000 mies now
Thread Starter
Burning Brakes
Joined: Jan 2009
Posts: 961
Likes: 0
From: Woodbridge, VA.
Shifting better now
Tran-X,,, appears to be working for me and I have the exact same problem.
Looking to rebuild in the fall if it can wait.
More here:
https://rennlist.com/forums/928-foru...ion-fluid.html
Looking to rebuild in the fall if it can wait.
More here:
https://rennlist.com/forums/928-foru...ion-fluid.html
Nordschleife Master
Joined: Apr 2008
Posts: 9,337
Likes: 4
From: Austin, TX
Not trying to hijack the thread here...
I kind of have the same problem. 90k miles on my '88S4, 10k HARD track miles and it is not slipping with some pretty nasty smelling Trans fluid... Any thoughts on what direction to take this thing? My mechanic did not want to change the fluid out figuring it would never shift again if he did as the new fluid would have to much lubricity relative to the old burned up stuff... I guess I should have been changing the fluid more regularly when I was HAMMERING the car as my track beast for so many years!
I kind of have the same problem. 90k miles on my '88S4, 10k HARD track miles and it is not slipping with some pretty nasty smelling Trans fluid... Any thoughts on what direction to take this thing? My mechanic did not want to change the fluid out figuring it would never shift again if he did as the new fluid would have to much lubricity relative to the old burned up stuff... I guess I should have been changing the fluid more regularly when I was HAMMERING the car as my track beast for so many years!
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Race Director
Joined: Sep 2007
Posts: 12,162
Likes: 383
From: Johnson City, TN
Several I've drained are full of a yellow-like fluid that is just plain nasty smelling.
I found a reference to it being the Porsche service fluid, but forget where I read it.
So long as it doesn't smell burned you should be ok.
I found a reference to it being the Porsche service fluid, but forget where I read it.
So long as it doesn't smell burned you should be ok.
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Nordschleife Master
Joined: Apr 2008
Posts: 9,337
Likes: 4
From: Austin, TX
^^^^
That is what my mechanic said and he is a BIG 928 fan! I trust him. I have another used (and we hope GOOD) transmission sitting in a parts car next to his shop... Waiting for the R&R... Gonna see if I can get this one to OCIC and back before the change. It is not slipping a lot at this point and it is just less smooth than I know it should be. I suspect the average person would not even notice a problem at all.
If I behave for the next month and don't put more than a few hundred miles on it will it last the 350 miles to OCIC and back??? I know...that is a loaded question... thoughts from you experts por favor!
That is what my mechanic said and he is a BIG 928 fan! I trust him. I have another used (and we hope GOOD) transmission sitting in a parts car next to his shop... Waiting for the R&R... Gonna see if I can get this one to OCIC and back before the change. It is not slipping a lot at this point and it is just less smooth than I know it should be. I suspect the average person would not even notice a problem at all.
If I behave for the next month and don't put more than a few hundred miles on it will it last the 350 miles to OCIC and back??? I know...that is a loaded question... thoughts from you experts por favor!