My brother-in-law is having problems installing the transmission in my Chevelle. He is working on the car in his automotive class and his instructor thinks there is a problem with the pump.

The input shaft doesnt seem to turn at all. Any reason that it shouldnt spin freely?

They removed the pump and loosened the bolts holding it together, then the input shaft spins freely. However, tightening everything back up again makes the input shaft unable to turn.

New 700r4

If the trans gear selector is in the wrong position will it cause this?
Operator error?
Problems during manufacturing?
Please help

Sorry if I have used incorrect terminolgy, etc. I have never done anything with transmissions.