Now that I'm nearing putting the rear end back in the car I need to know what fluid to put in. I will be following the service manual's procedure for flushing the differential. After that is says to put in positive traction lubricant, GM Part # 1051022. What can I use in place of this? Do I have to worry about using synthetic fluids? The rear end leaked only by the cover seal from what I could tell. What rear end fluid would you recommend? How much do I put in? How do I put the fluid in the rear end when its in the car? What should I use on the cover along with a new cover seal, RTV? Anything else I should know? o No: Thanks
2+ quarts of regular (not syn or syn blend) 80w90 & one small bottle of GM posi additive is what you need. Just using the qt bottle to fill the hsg... mix the small bottle of GM additive in partial filled qt bottle of 80w90 after 1st putting 6oz or so of straight 80w90 in the hsg. Hard to beat the GM additive in std type clutch type posi's.There are quite a few parts store limited slip additives, I've not had good luck with. For that reason, I buy the Gm additive by the case. The worst parts store limited slip additive I ever used was a blue paste in a toothpaste type tube type bought in the 90's Synthetics... Though I've used synthetic gear lubes, in particular SunVis 75w140 & Redline products, synthetic lubes often mess with pinion & axle seals Over 10 years ago, in our 1st use of synthetic gear lube, we did not have r/e housing & axle tubes totally 100% clean of previous std gear oil. The inside of hsg looked clean, but axle tubes still had some "dino" gear lube. the impending mix ended in an absolute mess. This was in a Dana70 in a Cummins Dodge Dually. Lot of fun pulling the wheels & tires & drums, replacing the gear oil covered brake shoes, removing the axles & replacing axle seals. For that reason, I'll only use synthetic lubes on fresh bench build, when customer demands it, & signs off on the leaking seal risk. For rear cover sealing, if you have a small bottle of Permatex gasket sealer, & can get a new rear cover gasket, go for, as it will make removing the rear cover easier at a later date. If not, RTV silicone, can be used, just make sure mating surfaces are clean. Gear lube will need to be added through fill plug on side of the center hsg. Pipe plug will come out with 3/8 socket ext & socket wrench. For filling I use a tool that looks like a grease gun with plastic tubing attached. Just more comfortable to use than fighting the qt bottles above the r/e hsg. Hope this helps. Got Posi? :3gears: Roger
