Transmission code

The problem is the check engine light comes on. The code is P0758. The light could come on right after you start the vehicle or when you driving down the road. I have already replaced the tranny with a used one out a junk yard and still have the same problem.

Before the tranny quick pulling all together and it multi codes. I talk to dealer and other transmission shops and that's where I got my info. I had someone at a trans shop tell me it could be the pcm, is that possible?

Any suggestion would be grateful.