I'm gonna use silicon, probably the same weight you suggested. I won't get a chance to do it till later this week. I had to order them from the hobby store, and they won't get here till Friday, which of course is the day I'm leaving out of town. Hard to believe its that easy. Is there anything else that I should know? Is there a certain kind of rubber gasket that I should use when I put the new ones together? Haven't seen the inside of the diffs yet, will there be a problem put the gears back into the new one? I know its not as serious as the trans, but still.