Owner had rear tires worn down, front tires new, we're seeing 8 inches in 10 rotations LR and 6 inches in 10 rotations RR difference from front tires. Not good, seems to have done some driveline damage.
Put two new tires on the back same brand and size as new fronts, seems to be a lot better but center diff whines under load, front diff chatters and bumps a little turning in reverse.
Factory recommended lube is just regular old gear oil, GL-5 SAE 90.
Not looking for a miracle in a bottle, but is there any lubricant that will work better in these differentials?