Transmission problem on 2000 Chevrolet Impala

I have a 2000 impala 3.8 engine,(Police car) The selector on top of the transmission won't move. The PNP switch is on the inside of this transmission some are on the outside could this switch be the reason why the selector won't move if so how do I replace it.

You have to diagnose the problem, it could be a failed PNP switch but could also be in the shifter, the interlock or cable. You'll have to find out. The switch is probably very easy to replace but I don't have a procedure for it.
If you want to find a Chevy specialist, here's our directory link for you: