Transmission Shifting late
Thread Starter
Heel & Toe
Joined: Apr 2019
Posts: 22
Likes: 4
From: Europe
Transmission Shifting late
1985 Corvette Auto
The car used to shift great but It had a leak, so I took it a garage to replace the seals. So they pulled out the transmission and installed all new seals now it doesn't leak but the shifts are incorrect.
Now instead of shifting from 1 to 2 at 2k rmp at low acceleration it does it at 2.5k. It only shifts early If I cut off the gas completely. On Highway It doesnt want to shift to 4th. Overdrive works, but 1 and 2nd postion on the lever does nothing.
So I thougth it was the TV Cable that was bad... We changed it and it still has the same behavior.
Now the garage is saying that a Shift Kit should fix it.
What you guys think is the problem?
Thanks
The car used to shift great but It had a leak, so I took it a garage to replace the seals. So they pulled out the transmission and installed all new seals now it doesn't leak but the shifts are incorrect.
Now instead of shifting from 1 to 2 at 2k rmp at low acceleration it does it at 2.5k. It only shifts early If I cut off the gas completely. On Highway It doesnt want to shift to 4th. Overdrive works, but 1 and 2nd postion on the lever does nothing.
So I thougth it was the TV Cable that was bad... We changed it and it still has the same behavior.
Now the garage is saying that a Shift Kit should fix it.
What you guys think is the problem?
Thanks
Melting Slicks
Joined: Mar 2002
Posts: 2,876
Likes: 764
From: Sligo PA
It sounds like they didn't get the TV cable adjusted properly. Try re-adjusting the cable and see what happens.
Summit racing did a pretty good guide on how to set the TV cable adjustment.
TV cable adjustment
Summit racing did a pretty good guide on how to set the TV cable adjustment.
TV cable adjustment
Last edited by Phobos84; Jun 21, 2021 at 12:04 PM.
Thread Starter
Heel & Toe
Joined: Apr 2019
Posts: 22
Likes: 4
From: Europe
It sounds like they didn't get the TV cable adjusted properly. Try re-adjusting the cable and see what happens.
Summit racing did a pretty good guide on how to set the TV cable adjustment.
TV cable adjustment
Summit racing did a pretty good guide on how to set the TV cable adjustment.
TV cable adjustment
Replacing the TV Cable produced the same result.
Thread Starter
Heel & Toe
Joined: Apr 2019
Posts: 22
Likes: 4
From: Europe
Finally got my transmission working again after 6 months, I am leaving the details in case someone has the same problem.
So after trying with new TV Cable with no success, they installed a shift kit for the transmission and the problem persisted... Then they spoke about changing valve system or something like that.
But in end and they decided to open the transmission, they found an O-Ring broken which was preventing the transmission to build pressure to swap gears, only at high rpm. After fixing that part the transmission is working again... even better than before
So after trying with new TV Cable with no success, they installed a shift kit for the transmission and the problem persisted... Then they spoke about changing valve system or something like that.
But in end and they decided to open the transmission, they found an O-Ring broken which was preventing the transmission to build pressure to swap gears, only at high rpm. After fixing that part the transmission is working again... even better than before
Race Director
Joined: Apr 2003
Posts: 17,700
Likes: 1,667
From: moraga ca
Finally got my transmission working again after 6 months, I am leaving the details in case someone has the same problem.
So after trying with new TV Cable with no success, they installed a shift kit for the transmission and the problem persisted... Then they spoke about changing valve system or something like that.
But in end and they decided to open the transmission, they found an O-Ring broken which was preventing the transmission to build pressure to swap gears, only at high rpm. After fixing that part the transmission is working again... even better than before
So after trying with new TV Cable with no success, they installed a shift kit for the transmission and the problem persisted... Then they spoke about changing valve system or something like that.
But in end and they decided to open the transmission, they found an O-Ring broken which was preventing the transmission to build pressure to swap gears, only at high rpm. After fixing that part the transmission is working again... even better than before
Safety Car
Joined: Mar 2017
Posts: 4,195
Likes: 1,318
From: LeClaire Iowa
I totally understand what you are saying if while changing the seals they screwed up the o-ring. If the o-ring just decided to go bad on its own while the seals were being replaced I can't see how they are responsible. Maybe thats why some shops don't want to work on 30 year old cars because they fix one thing and another thing goes bad in 2 miles and they are blamed. Dan
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