I'm having trouble with my rear diff leaking. It is a B/W 9Bolt. A while back we put a new posi unit in and just used rtv sealant (no gasket) and it started leaking.
Next-- pull the cover and used the gasket. Still leaking.

Do I need a new cover or is there some big secret I'm missing?

Bob

 

No offense intended, but sometimes it's not what you do, it's how you do it.

All the old gasket material and sealer must be removed. If you miss the slightest bit, it can leak.

I'll tell you how I do it. It may seem like overkill, but I never have leaks.

I scrape the surfaces (both the cover and the housing) with a sharp putty knife.

I brush them with a brass wire brush.

I whipe them with laquer thinner.

I apply a very thin small bead of sealer to the cover then I smear it with my finger to a very thin layer.

I then do the same to one side of the gasket.

I attach the gasket (side without sealer) to the cover and let it set up for ~10 minutes.

I then install the cover and let it set up for ~1 hour.

I add gear lube.

I drive with no leaks.

 

might want to hammer out the dimples around the bolt holes in the cover too.

 

Oh yea.

I do do that, just forgot to mention it.

I said "do do".

 

Actually both times were done at a friends house who does gear installs on the side. He's done a ton of them and is very meticulous. It seemed that everything was cleaned up good.

Bob

 

Make sure it's not the pinion seal leaking. A slow leak at the pinion seal will run back and drip at the bottom of the inspection plate.