transmission wont go in reverse on 1996 Volkswagen Golf TDI

when i shift in reverse it trys to backup then kicks it out of gear and grinds really bad. If the car is on jackstands and u put it in reverse it turns the tires fine but still sounds like it is grinding or really rough sounding. do i need a new transmission or is it worth having this fixed.However the car drives grat its a manual tranny

1 answer
If it is a manual it sounds like the synchronizers or the clutch.