Chevy transmission

I have a 87 Chevy truck with a 383 stroker and a 400 turbo trans with a 3500 stall torque converter. Is there a way to adjust trans to shift at higher or lower RPMS. The trans doesn't seem to change more than once. It changes smooth and it is possible it is changing into second as soon as it starts off. The rear end is geared very low or the trans isn't shifting into the highest gear. I have been told the modulator valve may have been adjusted or changed to make it shift this way. I appreciate any help anyone can give me.

Sounds to me like your modulator valve either has no vacuum or it is defective.

Thanks Oldf100fordman. I will check that out.

If a modulator didn't have vacuum, the transmission wouldn't shift out of first gear. I think the problem may be governor related. The transmission thinks it is going to fast for first gear, so it doesn't go into first.

76GMC1500


Years ago, back when I was still a Chebby man like streets, I bougth an Impala to use for a motor transplant for my 69 Camaro. It had a 327 and a 400TH. It had 1st and 2nd and no 3rd and it was simply a bad madulator. The Governor would force it from 1st to 2nd. That's been my experience with GM trans.

Quote: The Governor would force it from 1st to 2nd. That's been my experience with GM trans.

And that is the problem truckman is describing.

must be the week for th400's to goof off.....
mine is having difficulties downshifting...
replaced vac modulator, no help...
where and how does one adjust/replace the governer?????
**) :confused: **)