trans slips when cold?
Thread Starter
Racer
Joined: Nov 2009
Posts: 486
Likes: 1
trans slips when cold?
I have not checked the fluid today but I will when I drive home.. if it stops pouring down rain. TH350 trans and she was slipping in reverse and felt like it in 1st too. Once warmed up there was no problem. I have blown 2 TH350's in my 85 monte I use to have. If I remember correctly reverse/1st was first to go out :-( However, could it have anything to do with the modulator valve? From an earlier post about the trans said I need to replace that valve. Think that could be the problem?
Last edited by glarior; Nov 30, 2009 at 12:14 PM.
Melting Slicks
Joined: May 2002
Posts: 2,431
Likes: 52
From: Florida
The neoprene lip seals, when old, tend to not be pliable until warm/hot. This lets the pressurized fluid leak by instead of applying the drum. It's been my experience that the lip seals are the cause of slow engagement when cold assuming the fluid level is full. The modulator and or vacuum affects the up/down shift and not engagement. They make an additive that will soften the lip seals but I don't recommend its use. I believe it to be lacquer thinner or something similar.
Thread Starter
Racer
Joined: Nov 2009
Posts: 486
Likes: 1
That’s good to know.
I checked the fluid and it is low. Go figure its raining again but I will add some today.
My new question is.... Am I able to add ambient temp trans fluid to the hot transmission or should I wait until the trans is at ambient temp too?
I checked the fluid and it is low. Go figure its raining again but I will add some today.
My new question is.... Am I able to add ambient temp trans fluid to the hot transmission or should I wait until the trans is at ambient temp too?
Race Director
Joined: Mar 2006
Posts: 14,112
Likes: 28
From: Florida
The neoprene lip seals, when old, tend to not be pliable until warm/hot. This lets the pressurized fluid leak by instead of applying the drum. It's been my experience that the lip seals are the cause of slow engagement when cold assuming the fluid level is full. The modulator and or vacuum affects the up/down shift and not engagement. They make an additive that will soften the lip seals but I don't recommend its use. I believe it to be lacquer thinner or something similar.
If it truly is from the seal hardening then an ounce of brake fluid will help. At that point, you don't have much to loose.
Melting Slicks
Joined: May 2002
Posts: 2,431
Likes: 52
From: Florida
Never heard of that trick....what's in brake fluid that helps?
Thread Starter
Racer
Joined: Nov 2009
Posts: 486
Likes: 1
