you're supposed to back the bells and birfs with axle grease if they put 90 weight in there, they are going to have to flush it. i don't think it will mess up the birfs and bearings, but i would make them repack the bearings and birfs for the mess up. 90weight goes in the 3rd member. the inner axle seal should help prevent 90 weight from making it into the knuckles...are you saying that he filled your knuckles with 90 weight?
Yes he did. I pulled my hubs to replace the rotors and pads. You should have heard some of the words lflying out of my mouth! Plus my lap got drenched in oil/grease. I was like wtf there shouldn't be any green in here (marine grease).
ok so have them strip down the whole axle, replace all fluids including the dif, and have them repack all the bearings/birfs.
I only put about 20miles on the messup because of a front break prob, i just wanted to make sure it wouldnt seize up the birfs.