[volksworld]

the clutch is not disengaging completely and allowing the input shaft to spin...a syncronized gear is much more forgiving to this condition...the clutch might need to be adjusted,there could be oil or grease on the disc causing it to stick to the flywheel and/or pressure plate,a bad pressure plate not releasing evenly,a disc with a piece of friction material hanging off and dragging, or a worn or dry input shaft bushing in the back of the crankshaft could all cause this...sticking it in a syncro gear to get it to stop spinning then quick stuffing it into reverse will make it driveable but you're not doing your tranny any favors