Put TH400 back in, won't shift
 

Well, I've been creating several threads with different issues of my friends' '63 C10. It started with putting a new engine in (which is running great now, woohoo). When attaching the transmission he broke the pump, which he replaced and now the car moves, but: It won't shift out of first gear! My friend has an idea that the solenoid on the transmission for the electric kick-down might be causing it, but I haven't a clue. Can you pros help?

Thanks!

Re: Put TH400 back in, won't shift
 

do you have the vacumn line hooked up to the modulator?

Re: Put TH400 back in, won't shift
 

Yessir, he reports his vaccum is plugged in correctly to the intake manifold, and there is a good suction. I suspected this myself as possibly being a problem. Maybe his modulator is bad?

Re: Put TH400 back in, won't shift
 

The kick down circuit probably wouldn't keep it from shifting. I would bet you are correct and the vacuum modulator is bad or damaged and leaking vacuum. Without it functioning the trans will not shift out of first gear.

Re: Put TH400 back in, won't shift
 

Okay I will let him know. Replacing the modulator is cheap anyway and wouldn't hurt.

Re: Put TH400 back in, won't shift
 

If the modulator doesn't do it, you could look at the governor next. The symptoms are about right, but I have no clue how there could be any connection with a damaged pump. A more likely possibility might be that a small piece of debris from the pump somehow got into the valve body.

Ray