Had the rear axel service done at the dealer. They put part#89021677 lube in but not the additive part#1052358. When I questioned the dealer he said he had conflicting bulletins on wether or not it was needed. Stealth's proceedure in the maintainance section indicates it is needed. Has anything changed in the factory lube(grape stuff) or do I need the additive? Also why don't the dealers have correct info on this especially with all the rear ends being trashed?