I'm draining my diff tomorrow and I wanted to make sure I bought the right kind of gasket and sealer. The gasket is from autozone, it's a fel-pro part number RDS 55072. It says it's for 7 1/2 and 7 5/8 diameter ring gears. I got some blue rtv silicone gasket maker to seal the gasket, is this alright? How long should it dry before I drive the car? Would it be alright to back it out of autos after I change the gasket, park it, and let it sit for an hour or so? If it helps, my car is a 1988 camaro non-posi 10 bolt. I just wanted to clear it up so I don't screw up my diff. Thanks.

 

well blue RTV should be just fine for a slight sealant. just make sure your surfaces are clean and follow the directions on the tube. after you bolt the cover on i would let it sit for a minimum of 30 min for cure time to be safe then put the fluid in. I try and wait as long as possible to make sure it cures completely usually the cure period is on the back of the tube also. One word of warning i wouldn't put an excessive amount of sealant on because more does not mean better. Take your time and every thing should go good

 

Is there any difference between the black gasket maker and the blue one? Which is better for sealing diff. gaskets?

 

i always use the black and i never use a gasket. as long as you let it cure and make sure its clean, it will be fine.

 

Just get the high temp RTV sealant. Mine was red.

 

I swear by the Permatex Ultra Black. I use a paper gasket and apply a very light skin to each surface prior to installation. I install it wet and torque all the bolts down to spec. You can fill it right afterwards and drive it. I've never had a rear cover leak when I did it like this.

 

Permatex
Permatex
Permatex



good stuff...... people will debate between the blue, black, copper, ect....

but the fact is, they make the best stuff out there, and you cant go wrong with either of thoes 3 (or Permatex "The Right Stuff" thas good too)


just get some brake cleaner, and some shop rags... spray the cleaner on the cover and wipe it down good... same for the diff....

once its 100% clean, i usually use the Permatex by itself.... set up a thick bead, and let it cure for 3 or 5 mins... then stick the cover on.

 

Right one. Yes. An hour is fine. Yes.

 

permetex ultracopper is all i use, cost a little more but i ithnk it the best. ultra grey is also very good ,but i don't like it as well. i don't really use rtv o nthe rear other than to stick the gasket to the cover.