98 k1500 suburban rear differential was leaking so I removed the cover, drained the oil, replaced the gasket, reattached the cover, & filled with gear oil. Tightened bolts to 30 lbs with torque wrench. And….still leaking. Leaking worse! What did I do wrong? Any advice, help?!?! Used

FEL-PRO Axle/Differential Gasket RDS55028-1

 

Did you use a full synthetic gear oil? Full synthetic oils require a viton gasket/seal. If this is the case, and I do not know that fel pro, might be your issue.

 

Thank you for the reply. I appreciate the help. I did not use synthetic oil. Used this STP gear oil. Any other thoughts? Anyone out there think it is a bad gasket or have another recommendation?

 

post a pic of the leak area.
if leaking from the cover....did you clean the mounting surfaces? if from the pinion or axle seals...if the diff vent plugged?

 

Thanks for the reply tech2. Here are leak pics. Seems to be coming from the bottom. I did clean the surfaces, used parts cleaner and also scraped off the old gasket remains. Seemed more like a rubbery goo than a true gasket. I read elsewhere to only scrape with a plastic tool. I did use a metal scraper and a screw driver. Did I damage the cover? If so how to remedy? Anyone think I should try Blue Devil Oil Stop? Redo the gasket with a sealant gasket maker as well?

 

You don't want to scrape on a machine matted surface which is not the cover. If it's leaking around the threads, I might suggest a metal washer and O ring.

 

drain the diff; catch and save the fluid. clean the surface and dry wipe with brake cleaner. throw the gasket out and use rtv. I "like the right stuff"

 

May be an optical delusion but looks to me like the cover is bent outward where it's leaking - maybe got pried open there??

 

Thanks again to all who have replied. I am curious about the possibility of a bent cover. I don't think it is, and I know I didn't have to pry hard to separate it when I drained it the first time. I think I will drain it and use RTV...hopefully that will settle the problem. Anyone advise against replacing the cover?

 

Place to cover on a flat surface, sets flat it's good.