TH400 transmission problem
Thread Starter
Pro
Joined: Oct 2001
Posts: 668
Likes: 26
From: Wadsworth Ohio
TH400 transmission problem
My 74 has hasn't been run for 7 years now when I take it out it won't shift out of 1st gear. It was less than a quart low of fluid but even filled up it won't shift up. Any input on solving this problem will be greatly appreciated. Thanks, Tom
Drifting
Joined: Oct 2007
Posts: 1,317
Likes: 22
From: Marina CA
Take it out and run it up to a higher speed and if shifts 1-2 and 2-3 at higher speeds and with firm shifts, it's shifting by the governor. That confirms what the other poster said about the modulator. It could have a bad diaphragm, loose or kinked hose or be disconnected. If you pull the hose off and ATF oil is present the modulator is done.
Thread Starter
Pro
Joined: Oct 2001
Posts: 668
Likes: 26
From: Wadsworth Ohio
Thanks to all who replied it turned out that the vacuum hose was disconnected at the intake manifold. This is what is great about this forum everyone is willing to help whenever someone is having a problem. Thanks again, Tom
