Tranny won't go into reverse but lights come on and drive works fine

What type of vehicle is this and what exactly is it doing? Also when was the last time you checked your fluids?

It's a 1995 ford f350 I put it in reverse and it won't move drive works fine and its full of fluid

Time to take it in and have it checked by a reputable mechanic. It sounds like the insides are having a problem. The lights portion is handled by switches in your linkage and have nothing to to with the performance of the transmission. You could have a broken band or an adjustment out of spec.

I was thinking the same thing thanks for your help