2nd Gen Non-Engine/Transmission Dana 80 oil change...

[Ralph Heron]

Had some fun pulling off the rear diff cover



After removing the ten bolts, I was expecting to find a gasket between the cover and the pumpkin... but after some swearing and some handy working with a putty knife and a hammer (tap,tap,tap,... ), got the lid off to find that there was only grey permatex. The problem with this is that it was really tough to get the putty knife in this small gap...



Going with the PML cover, so oil changes should get much easier but am wondering if I should shell out the $25 for a new gasket (or if this is just a waste of money). PML cover is pretty nice (has a plug on top for fill, a plug for level and a drain on the bottom (with magnet)...



Another note: at about 10k miles, the truck started getting a drip from rear diff cover which the dealer "fixed" (maybe they pulled the gasket)...



BTW, I'm replacing the stock gear oil with Mobil 1 (75W140) and some LSD additive... how much do I need to fill the rear end and the PML ??



Rgds,

Ralph-

 

[CyberRanger]

Cool trick for diff covers & gaskets...



Yes, a conventional gasket is expensive & doesn't seal any better than the form-a-gasket method the manufacturers use now. The trouble w/ the form-a-gasket method is it is pretty stinkin' difficult to get the cover off when changing lube & has to be cleaned off completely before resealing.



Here's what I do. I buy a conventional paper-style gasket & am able to reuse it. I coat both sides of the gasket w/ a thin, but uniform layer of Permatex Ultra Blue RTV. I leave the diff cover metal completely clean & dry. The differential housing surface I first clean & dry completely & just before I bolt the cover on, I coat the diff housing surface w/ a very thin layer of light oil. This allows the gasket to seal, but still makes it easy to get off to change my gear lube. It also lets the gasket adhere to the cover & it stays in place. When you change your lube you can simply leave the gasket on the cover, wipe down the housing surface & put on another coat of light oil.



Just make sure you uniformly torque the cover bolts to the proper spec to make sure you don't crush & split the gasket.

 

[dodge cummins]

i just did it to my 96 3-4 weeks ago and mine also had grey sealent. i just scraped everything off real good. i then sprayed carb cleaner all over inside the diff cover and got all contaiments off,i also sprayed gasket remover anywhere there was still gasket left. i then dried everything real good and i pre-purchased the BLACK rtv silicone gasket maker. i put the silicone the whole length of diff cover and also around the outside of the bolt holes. i reset the cover back on the axle torqued the bolts back in by hand. i did it after work so after that i just let it sit or cure overnight. 7am the next day i filled first with the 7 oz of limited slip additive and about 3 and a half quarts of mobil 1 75w140. all is good now. i will change her again in about another 100,000 miles.