Originally Posted by
CarbonJoe
Crash resistance. The diff with 500K or heavier oil in it allows for some give in the event of a crash, and it almost acts like a spool. I've heard of people using gray cleaning putty (but that's a PITA to get out) or one or two foam ear plugs. This almost makes it like a locking diff, but still has some give.
The thing I don't like about a front diff is it's not very consistent from the start of the run to the end, even using cleaning putty. It heats up/breaks down and is a lot softer by the end of the run.