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Old 11-29-2010, 08:17 PM   #1
cppursell
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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!
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Old 11-29-2010, 08:38 PM   #2
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Re: Put TH400 back in, won't shift

do you have the vacumn line hooked up to the modulator?
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Old 11-29-2010, 08:54 PM   #3
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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?
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Old 11-30-2010, 05:10 PM   #4
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Re: Put TH400 back in, won't shift

Quote:
Originally Posted by cppursell View Post
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?
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.
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Old 12-01-2010, 04:10 AM   #5
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Re: Put TH400 back in, won't shift

Okay I will let him know. Replacing the modulator is cheap anyway and wouldn't hurt.
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Old 12-01-2010, 02:50 PM   #6
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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.

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