Transmission

Is it possible for my pcm to be bad. My trans slams in reverse and once in a while it will shift hard. But my bigest problem is the trans will drop back to 2nd after keeping your foot on the gas over 45 and I just changed it and now the send does the same I'm wondering if a pcm would cause this

Is it possible for my pcm to be bad. My trans slams in reverse and once in a while it will shift hard. But my bigest problem is the trans will drop back to 2nd after keeping your foot on the gas over 45 and I just changed it and now the send does the same I'm wondering if a pcm would cause this
You just changed the pcm? Stop the guess work here and have the car scanned on a trans function scanner to look at solenoid and slippage error/functions, this will tell you if the electronics are an issue or other inputs are skewing the trans operation.

stuck in second is usually shift solenoids, many posts on here about that. its a 50 kit if you dont mind dropping the pan and valve body.

Reverse shifting hard isnt due to shift solenoids.
My guess is your PCM isnt controlling the pressure.
Pressure control solenoid can be checked with an ohm meter.
Or you can get a good scanner to read it while you drive.
Reverse has higher pressure than forward gears.
Trans will default to 2nd gear if anything sets a tranny code.