Ok, based on my previous question I went and picked up 2 tubes of black permtex (meets Ford spec) good for valve covers, water pumps, oil pans, trans pans, diffs, etc.

I noticed that "full cure time" is 24hrs. Do I really have to let it sit for 24hrs before I drive it? What time frame do ya'll let yours sit after changing the fluid? I was thinking about doing it Saturday Night, that way it will be 12-20 hours before I drive it again, think that will work?

 

The longer you let it cure the better it will be. It will work after 12 hrs.

 

My diff. leaked after a shop replaced the spider gears. The guy must have used an entire tube of sealant but I don't think he cleaned it properly before re-assembly.

I couldn't live with a leak so I fixed it. It didn't come from Ford with a gasket but I intalled one made by Felpro and used a thin layer of Permatex 16B (Black Silicone Adhesive Sealant) on both sides of the gasket. The most important thing is CLEAN both surfaces down to shiny metal.

I refilled the diff. as soon as I finished tightening the cover bolts (almost zero cure time) and it didn't leak. Maybe I just got lucky but I think cleanliness is next to Godliness in this situation.

 

Your lucky, the aftermarket makes a gasket for the 8.8. I have the 9.75, so no gasket.

Ok, I figured that but just wanted to make sure I did not need to go the full 24.

Thanks

 

I clean the cover and axle flange, spray it down with brake clean, slap some RTV on it throw it together and go. Never had one leak yet.

 

Thats good to know. I figured doing it saturday night will allow it to sit 12-20 hours before I use it again, so that will be my plan.

Thanks

 

Also, it'll take less RTV than you'd think; I think where most people screw up is that they get carried away with the stuff. About a 1/8" thick bead, don't forget to go around the bolt holes as well, will do fine.

 

I would agree with what Quintin said.

Run the bead, let it set up for about 20 minutes, then install the cover with all the bolts HAND tight, as tight as you can get them with a socket and extension, no ratchet. Let it sit overnight, torque to specs the fill the difff with lube.