No 1st 2nd or 3rd but R works

Yeah sure. I'd try the cheap stuff first. Oil level, linkage / cable adjustment then a pressure test. If you have reverse but no 1-2-3 it could be the rear clutch is toast or the hydraulic circuit for the rear clutch. Either way it sounds like the trans is very tired & in need of a rebuild.

3000 bucks for a 904??? Wow!! Who rebuilt it Louis Vuitton???