TH-400 Will Not Upshift

03-17-2013, 05:26 PM
Updated Post -
1970 Chevelle. Was hoping to reach someone that can offer advice.
It is a Rebuilt trans, but it sat for 5 years in dry storage. Stock valve body. Will not shift into 2nd or 3rd, stays in low even up to 4500 RPM. Replaced Vacuum Modulator, still same. With shifter in low gear, will stay in low, even on deceleration. In 2nd or Drive, it stays in Low even up to 4500 RPM. will freewheel/idle when you let off the gas. Has manifold vacuum at modulator.
Checked the governor, I don't know how they work, but both weights just flop around by gravity, not spring-loaded. Pulled the one from the old trans, and it seems to be the same way.
Guess I will drain fluid and drop the pan, and look around at the valve body.
Hoping for some help on what to look for.
Thanks a bunch, -Jim.

03-17-2013, 11:06 PM
Folks, this is an unintentional duplicate thread.

Here's a link to the relevant active thread:

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