Use Mopar "Hypoid Gear Additive, Friction Modifier" - - part number 4318060 with regular lube. One option for synthetic: "AMSOIL Severe Gear is compatible with most limited-slip differentials. If limited-slip differential chatter occurs, add AMSOIL Slip-Lock™ friction modifier additive." http://www.amsoil.com/storefront/svo.aspx?=zo=1606470 Gary H. > -------Original Message------- > Since I have to put lube in my 4 speed and rear differential, I > thought it might make the 4 speed tranny shift better. I can ask > Brewers their opinion on what or if on the tranny lube, but who to ask > on the shur-grip diff.?.......................MO -- -- -- Please address private email -- email of interest to only one person -- directly to that person. That is, email your parts/car transactions and negotiations, as well as other personal messages, only to the intended recipient. Do not just press "reply" and send your email to everyone using the general '62-'65 Clubhouse public email address. This practice will protect your privacy, reduce the total volume of mail and fine-tune the content signal to Mopar topic. Thanks! 1962 to 1965 Mopar Clubhouse Discussion Guidelines: http://www.1962to1965mopar.ornocar.org/mletiq.html and http://www.1962to1965mopar.ornocar.com/general_disclaimer.html. -- You received this message because you are subscribed to the Google Groups "The 1962 to 1965 Mopar Mail List Clubhouse" group. http://groups.google.com/group/1962to1965mopars?hl=en.