CarTalk.com Best of Deals Car Reviews Repair Shops Cars A-Z Radio Show

Gm 700 trans output shaft will not turn

was working in vehicle taken out of,once installed output shaft acts like it will not come out of park. converter was installed correctly.

Pull the tail piece and check the parking pawl.

Is the shift lever on the transmission moving freely by hand? You may think it’s shifting out of park but it may not be. Check it visually. Is the shift linkage connected?

the shift lever is being moved by hand under the truck.i try every thing one by one .p r n d etc. i have a yoke attached and a pry bar to move it. its like it will not come out of park.the shift lever acts like it is changing gears.

I would also check the pawl first. Normally, that output shaft wont be too easy to turn but if its locked more than likely its the pawl. Will it turn at all in either direction ??

transman

i’m beginning to think the guy that installed the trans didn’t seat the converter right,bolted it to the block then realized what had happened .so then he loosened it seated it right and decided not to tell me about it.do you think that could have locked up the output shaft? thanks.

Actually, that was my first thought too and it’s not a rare thing to happen.
This is why that during an automatic transmissioninstall the transmission should mate up to the engine without being excessively forced and why it’s a good idea to try and rotate the converter by hand before installing the converter/flex plate bolts.
If it won’t rotate easily you know there’s a problem.

could that have locked up the rear shaft?

I can’t say for sure but I wouldn’t rule it out. I’m not a GM trans pro (leave that to Transman) and my memory is very fuzzy due to the passage of so much time but it seems like we had a Subaru into the shop one time in which another shop had made an error while installing the transmission.

It seems the story was that the trans was locked and they attempted to force the issue by towing the car to “free it up”. (bad choice of words and technique)
What came loose was the center of the flex plate. The center section with mounting bolts twisted out and remained attached to the crankshaft; and the car then became a free-wheeler so to speak.
This was traced back to the converter not being seated on all of the splines. (3 sets of splines in this case and they missed the last set)

No, if he didnt seat the converter right, normally it would break the pump rotor. Check the pawl, make sure its releasing.

transman

that answered my question . i haven’t forced anything yet.thanks for all the help.