to stop the CRUNCH, push the clutch in, wait two seconds, then try reverse. The crunch is from the gearsets still spinning.
I never have an issue, and now that this thread popped up I tried to figure out exactly what causes it... A good delay between pushing the clutch in and then going for reverse helps a lot I've found, not to mention I didn't have ANY issues today after figuring that out.
I know, I've got too much time on my hands, but I wanted to understand the issue more. If you're at the gate for reverse and then push the clutch in while pulling it will grind, clunk, and fight you. Relax... Stay in neutral, clutch in, count to two, go to reverse, BINGO!
If it's not that simple you're either running Royal Purple in your tranny or you're trying too hard LOL