bob54, new to your forum. Thanks

[bob54]

New to your forum, have been turning wrenches for way more yrs than not.
I recently purchased a 1978 K10 pick up to rebuild. It is in fair to good condition.
Let me say right up front , I dont really know much about automatic transmissions.
This 350TH has a couple of issues: first it wont lock in park, sounds like its jumping a gear
when on a very slight slope. Second, It has no kick down, passing gear, linkage or cable any where.
I hope someone can tell me which it had from the factory so i know what to look for.
I will probably be changeing out the carb, one on it was only put on to sell the truck. It works
but not real good.
Would appreciate any help i may get. Thanks

 

[burnoutsAndRotorblades]

What carb does it have on it?

I am not 100% sure, but don't the TH350's use vacuum pods on the side of the trans to do kickdown? If there is no vacuum line form the carb to trans, that could be one issue.

If it is doing what you say it is in park, your parking pawl is probably bad in the trans. Either use the E-Brake, or fix the pawl. There are youtube videos on how to do it. Once again, I'm not an expert, but I think it can be done by removing the tailshaft housing from the trans.

Here is a possible solution in this video: