help gear grinding
 

tranny grinds while at high rpm's and shifting into next gear. what can it be?

Sounds like your synchros to me. I had this problem several times when I had my 92 eg w/ JDM H22 swap.

what is it. what is the purpose of this part. where is it located

Basically if your not familar with it, you'll have to have the tranny rebuilt. You could try and have your tranny fluid changed and see if that helps. Try that GM syncromesh fluid. I heard it helps.