Sealer With Differential Cover Gasket?

hikerboy · February 28, 2011

Will be changing the rear axle fluid on my '05 Z-71 1500 Sierra soon, I picked up a Fel-Pro paper differential cover gasket from the local NAPA store.......should I install the gasket with something like Permatex Form-A-Gasket #2, coating both sides of the gasket, or just install the gasket dry, or perhaps with a light coating of grease to hold it in place? Just want to get a "leak free" installation. Thanks for the help!!

Westlotorn · February 28, 2011

A little permatex spread as thin as you can does two things for you, first it seals small scratches that could be a leak path and second it helps hold the gasket in place for installation. It needs to be on both sides of the gasket because scratches or imperfections can be on either side. Another option is to use Silicone sealer with no gasket. If you bump the diff cover with a gasket in place it is less likely to leak. If you bump the same differential with silicone sealer it sometimes opens a leak path. I have used silicone in all my Chevys since 1984, I saw it was OEM on my 84 Suburban Diesel so I figured it was good enough for me.

jwhjr · February 28, 2011

Just use the Permatex Ultra Grey with no gasket and you'll be fine. Going on 2 yrs with no leaks on mine.

88K5 · February 28, 2011

I have always used permatex ultra black. Only need a little on the cover side. The axle housing face is machined so it is smooth and flat.

I uasualy don't even use a gasket for diff covers. Just run a bead around the cover and slap it in place.

Been doing it like that for 25 years and never had one leak.

K1500Tech · February 28, 2011

I have just the paper gasket on mine with no leaks

txab · February 28, 2011

I have just the paper gasket on mine with no leaks

+1

hikerboy · March 1, 2011

Thanks for the help, now I just need some warmer and drier weather!

tanked_darren · March 1, 2011

Just use the Permatex Ultra Grey with no gasket and you'll be fine. Going on 2 yrs with no leaks on mine.

I have always used permatex ultra black. Only need a little on the cover side. The axle housing face is machined so it is smooth and flat.

I uasualy don't even use a gasket for diff covers. Just run a bead around the cover and slap it in place.

Been doing it like that for 25 years and never had one leak.

+1

I use copper permatex just in case my diff heats up to several hundred degrees