Chevelles.com banner

1 - 7 of 7 Posts

·
Registered
Joined
·
4 Posts
Discussion Starter #1
I have a 70 Chevelle with a factory staple shifter. I have been experiencing the transmission going into gear intermittently at a cold start up. Sometimes it goes into gear no problem. Other times there won’t be any gears. I had thought that it’s a cable adjustment but was told by two transmission shops (Aamco & Speedy) that there is no problem with the cable adjustment. Speedy seems to think it’s the seals. I had a new carpet installed and it appears to lay on top of the cable or possibly bunching up. Wondering if that’s the problem. I have pulled up on the shifter when putting in gear and that seems to help. I do notice when it does not go into gear that I do not hear the selector on the transmission moving. When driving the car it shifts fine without any issues. Any ideas. Thanks Tom
 

·
Premium Member
Joined
·
4,795 Posts
Had several TH350's with cold engagement issues and was told it was seals. Both were older units in cars that had been sitting along time, so easy to believe. Both ended up with 700R4's
 

·
Premium Member
Joined
·
1,491 Posts
if it mostly occurs cold , at first start up of the day and is better once warm; the problem is the internal o rings, ie seals. They harden over time and take longer to expand to hold pressure. With care , they will last some time yet, but the fix is a rebuild
 

·
Registered
Joined
·
4 Posts
Discussion Starter #4
Sounds like a seal issue requiring a rebuild. Would an additive help until I get to the rebuild?
 

·
Registered
Joined
·
168 Posts
If it only does it when cold the piston/lip seals are getting hard as Harold mentioned. They do make additives to help soften the seals up which use to be a mixture of kerosene and tranny fluid. Don't know what they use now. But your looking at a rebuild soon.

John
 

·
Registered
Joined
·
4,430 Posts
Or plain old brake fluid.....
 

·
Premium Member
Joined
·
1,491 Posts
when you pour an additive in , you start to clock to rebuild time. Yes , it will expand the seals and will work better .....for a while. It NFVER stops expanding so finally the seal ring pops out of its groove and its overhaul time
Brake fluid was an old car dealer trick. By the time it quit working , the 30 day warrantee had passed
I once poured ATF in a master cylinder with the same results. I sucked it out with a pump immediately but it still ruined ALL the brake rubbers
 
  • Like
Reactions: 71350SS
1 - 7 of 7 Posts
Top