Trans problems

[1978chevybigten]

Got the fresh rebuilt trans in last night thought everything was going good. Go to drive today and she's stuck in 1st. What could cause this? The modulator is hooked on the carb I'm going to switch it to the intake. Could that be the problem?
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[1978chevybigten]

Switch the vac to the manifold and got the same results. It won't even up shift in manual. My neighbor took it for a spin and said the valve body is sticking. When we installed the shift kit. The 2-3 shift assembly was sticking. And the valve body was burred. We sanded them down but maybee we didn't get them all. Should I try to fix that or just buy a new valve body?
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[INSIDIOUS '86]

What trans? Modulator should be hooked to full manifold vacuum. If the shop is ignorant in transmission building beat practices they could have taken the valvebody apart and not deburred any of the valves or gotten rag lint on them. Either causing a stuck valve.

Also check your linkage make sure it's adjusted correctly
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[1978chevybigten]

Th350 We rebuilt it. It's hooked to manifold, we deburred All the valves and used compressed air to clean it. And the linkage is adjusted correctly to my knowledge. I'll double check. Would the best bet be to drop the valve body and re clean everything?
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[INSIDIOUS '86]

Yah drop it and run through the valves again. Check the valve size and the body bore size. If they are loose then it's possible they can jam slightly sideways and that means the body needs to be replaced
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[gchemist]

My tranny builder said a valve may get stuck because of a shift kit. He gave me these instructions.
Speed up in Drive, drive just about the point it shifts to 2nd, turn off engine (don't lock the steering wheel!), let it roll forward a few feet then crank it back up, slow down and speed back up. It should unstick the valve.

[clinebarger]

Pull the governor, Inspect for a stuck valve....Hold the weights closed & shake the governor....Should hear the valve "rattle".
Check for a stripped or apple cored governor gear.

[1978chevybigten]

Thanks for all the info guys, I'm going to replace the governor the gear was chipped a little and pull the valve body and see what's going on. If I can't fix it I'll buy a valve body from summit.
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[sqzbox]

Originally Posted by 1978chevybigten

Thanks for all the info guys, I'm going to replace the governor the gear was chipped a little and pull the valve body and see what's going on. If I can't fix it I'll buy a valve body from summit.
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Woah bud, Change the gov first. 1 thing at a time. If that doesn't work, then go for the valve body.

[1978chevybigten]

Originally Posted by sqzbox

Woah bud, Change the gov first. 1 thing at a time. If that doesn't work, then go for the valve body.

Thats what I was planning on.
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[rs72z]

Originally Posted by clinebarger

Pull the governor, Inspect for a stuck valve....Hold the weights closed & shake the governor....Should hear the valve "rattle".
Check for a stripped or apple cored governor gear.

This^^^^^

[1978chevybigten]

Replaced governor. Nothing changed, talked to a local trans shop and he rebuilds th350's for $300 -_- we have already spent that and plus some. Guess I should have got some quotes first lol. Going to drop the valve body. It's possible I used the wrong gasket? I guess we will find out.
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[1978chevybigten]

pulled the valve body and the 1-2 valve was stuck. got everything smooth and moving good. going to put everything back together and hopefully fix the problem.

[INSIDIOUS '86]

Sounds good. Let us know!
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[1978chevybigten]

Got everything back together now fluid and test. Hopefully she shifts!
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[1978chevybigten]

Well she's still in first, I think the shift kit plate is causing it. The gaskets they sent dont match the plate they sent us. Or any of the bolt holes and now I can't find the original plate. Im surrendering and taking it into the trans shop.
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[INSIDIOUS '86]

What kit was it?
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[1978chevybigten]

its a trans go from rock auto atp makes them.

[1978chevybigten]

trans has been in the truck for a week and is shifting good! very pleased the builder took out the spring cushion and added another steel. and the reason for the trans not the shift was i put the detent control valve in the wrong way. so it wouldnt upshift.