My diffs were ok too when i did the 4 spider mod. The cups were slighty worn but the spiders were perfect along with the ring and pinion. I think it was because it was a .21, I heard that the diffs were stronger in the older savages. I went with GH aluminum diff cups and 50k in the front and 30k in the rear. Hopefully i wont have any diff problems for awhile. (fingers crossed)