A833 4 Speed Problems.

The key words are "grind into reverse" Either you have a pilot bushing that's too tight on the input shaft and trying to drive it, or a serious misalignment problem, or you have a clutch problem.

With the clutch pedel depressed, how much feeler can you get between the disk and pressure plate?

I once had a clutch that would not realease clean for speed shifting. In fact, I could shift the car just as fast WITHOUT using the clutch. I fought that for weeks (scattershield, no bottom pan) finally tore it out and there was debri that had worked it's way in the outer area between the rear of the pp and the cover. It prevented the pp from coming back and releasing clean