i wanted to change my gear oil and posi fluid so i drained it all then cleaned everything up...i then ran a bead of perma-tex around the rear and put the cover back on...it was squeezing gear oil out the bottom of the diff cover, so i drained it all again and did the same thing but this time i let the car sit overnight to let the tex cure better in hopes it wouldn't leak...well it still does...what am i doing wrong?...help me out, thanks guys

 

Did you take a razor to it and remove ALL traces of old gasket? Plus, did you put on a new gasket? If so, then try cleaning up the surfaces with degreaser first, then coat the gasket with silicone and press it to the housing, wait about 5 minutes then press the cover on. Torque the bolts to 30 ft lbs and see what happens.

I've only pulled the cover and replaced it once, but didn't have any problems with leaks...

 

If you are not using a gasket. That could be your problem. Using RTV alone will work, but you have to use it on a clean surface. Its best to use a GM gasket & either Permatex Black RTV or GM's GMS. Your leak is probably coming around the threads of the bolts at the bottom.