th400 problems
Thread Starter
Heel & Toe
Joined: Oct 2005
Posts: 17
Likes: 0
th400 problems
I have a major leaking problem with my th400...first off the car only gets driven about 4 time a year, 3 times around the block and the 4th is to corvette magic... (corvette dragrace/carshow) we have been going since 91 with no problems until the last two years. the car gets run hard back to back 2 drivers..well the last two years we have been DQ'd because the tranny will all of a sudden burp alot of tranny fluid..which looks like its coming from the dipstick? so what is happening? too much line pressure? does it need a rebuild or is there something i can check?
Thanks for your help
-Doug
Thanks for your help
-Doug
Melting Slicks
Joined: Feb 2003
Posts: 2,529
Likes: 27
From: Auburndale Florida
2025 C2 of the Year ('64-'66) Finalist - Unmodified
St. Jude Donor '03-'05-'06-'07-'09
Doug I have the same issue with my unmolested 72. Mine is leaking form the shifter seal, the O rings are shot on the vacumm modulator and dipstick, front an rear seal are leaking....good news the pan is not leaking.
I have just removed mine form the car to go through. But if the O rings are shot on the dipstick tube or modulator. That is an easy fix.
Ck it out if that is the problem we can step you through it
Best of Luck..Mark
I have just removed mine form the car to go through. But if the O rings are shot on the dipstick tube or modulator. That is an easy fix.
Ck it out if that is the problem we can step you through it
Best of Luck..Mark
Thread Starter
Heel & Toe
Joined: Oct 2005
Posts: 17
Likes: 0
but mine does not leak normally.. even when its a hot day at normal temp...it only does it when run about 8 time down the track it burps and the doesn't leak at all..and when i mean out of the dipstick tube i mean out the top not around the seal to the tranny. that why i was thinking it might be some type of pressure issue?
Melting Slicks
Joined: Feb 2003
Posts: 2,529
Likes: 27
From: Auburndale Florida
2025 C2 of the Year ('64-'66) Finalist - Unmodified
St. Jude Donor '03-'05-'06-'07-'09
Originally Posted by cydways
but mine does not leak normally.. even when its a hot day at normal temp...it only does it when run about 8 time down the track it burps and the doesn't leak at all..and when i mean out of the dipstick tube i mean out the top not around the seal to the tranny. that why i was thinking it might be some type of pressure issue?
Thread Starter
Heel & Toe
Joined: Oct 2005
Posts: 17
Likes: 0
Originally Posted by Hinz-73
Do you have a shift kit installed?
do you think an after market cooler is needed?
Le Mans Master
Joined: Oct 2006
Posts: 7,123
Likes: 433
From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
There is a vent on top of the trans if I remember correctly. If it gets plugged the fluid can burp up the dipstick tube. Or just build too much pressure and force juice out the modulator/shift linkage o-rings.
May not be it, but I'd look. Might be a cheap fix
May not be it, but I'd look. Might be a cheap fix
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