Automatic Transmission Problem
Thread Starter
Instructor
Joined: Sep 2001
Posts: 247
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From: Marcellus New York
Automatic Transmission Problem
I had a problem with my 91 C4 that occured several times last summer when the temperature was in the 90's or above. After driving for a while, the trans started slipping in reverse. Not real bad, just enough to notice when I was backing out of my driveway uphill to the road.
All else seems fine, shifts OK, perhaps not quite as crisp when its hot, other than that, its fine. Never any problems in reverse when the car is cold. The car has 55K miles on it. Any ideas?
I'd like to get this figured out before I get the car out this spring.
All else seems fine, shifts OK, perhaps not quite as crisp when its hot, other than that, its fine. Never any problems in reverse when the car is cold. The car has 55K miles on it. Any ideas?
I'd like to get this figured out before I get the car out this spring.
Race Director
Joined: Feb 2004
Posts: 12,517
Likes: 19
Hopefully your problem is as simple as a valve hanging up a bit in the valve body. This can be dropped and cleaned without dropping trans. It could be as serious as worn clutches.
The atsc shop manual lists about 20 or more possibilities for slipping in reverse. If you like I can start listing them. Most are bad news so I won't list them to depress you unless you wish.
The atsc shop manual lists about 20 or more possibilities for slipping in reverse. If you like I can start listing them. Most are bad news so I won't list them to depress you unless you wish.
Last edited by Pete K; Feb 11, 2005 at 08:22 AM.
Thread Starter
Instructor
Joined: Sep 2001
Posts: 247
Likes: 0
From: Marcellus New York
Originally Posted by Pete K
Hopefully your problem is as simple as a valve hanging up a bit in the valve body. This can be dropped and cleaned without dropping trans. It could be as serious as worn clutches.
The atsc shop manual lists about 20 or more possibilities for slipping in reverse. If you like I can start listing them. Most are bad news so I won't list them to depress you unless you wish.
The atsc shop manual lists about 20 or more possibilities for slipping in reverse. If you like I can start listing them. Most are bad news so I won't list them to depress you unless you wish.
By the way, my in-laws live in Nanticoke.
Thanks
Race Director
Joined: Feb 2004
Posts: 12,517
Likes: 19
Boy, small world. I have met a few forum members who, by coincidence have roots in the wyoming valley. Hopefully your problem is simple. It never is for me. The seperator plate does wear out. The 87 and later models use a specific plate to match each specific valve body. It has a 2 letter code stamped into it. Do not use a generic plate. Buy the exact one from the dealer after you remove yours and confirm the code. I have part numbers to match each letter code if your dealer parts guy is stupid. The reverse boost valve is another easy to check part after pan is down. It can be removed from the pump through the bottom easily. 2-3 shift valve in valve body is another. The last easy possibility is the lo overrun valve in the aux valve body could be sticky. Good luck! Pete
Thread Starter
Instructor
Joined: Sep 2001
Posts: 247
Likes: 0
From: Marcellus New York
Originally Posted by Pete K
The seperator plate does wear out. The 87 and later models use a specific plate to match each specific valve body.
I was all set to buy a generic one.
