I've got an 8 3/4 rear end with a 742 case third member.

I made sure the surfaces were clean, positioned the gasket and gradually tightened the bolt in a star pattern, and then torqued the nuts to the specified 45 foot-pounds. Added fluid.

Come back the next day and there's a pool of gear oil on the floor beneath the carrier, and the point at which the third member and the axle meet is wet with gear oil.

There's no obvious damage to the mounting surface of the 742 case or the axle housing.

This is my first venture with an 8 3/4.

What should I do next? Use gasket goo? Or form-a-gasket?

TIA

--Walt Jackson

The way I did mine was I put silicon on the housing part, then the gasket, then the case. Use the mopar high temp differential silicon - good stuff, light grey color comes in tubes from your dealer parts counter. I got the tip from someone on here - that way you may be able to reuse the gasket when swapping carriers if you suck the oil out the fill plug.

Are you sure its not dripping down from the fill screw or pinion? Get the carrier spotless to see possible cracks.

I run a flat file over the gasket surfaces to be sure there are no burrs, nicks or high spots.
Glueing the gasket to the housing is a good tip, I do that on my 8 3/4s and get many leak free gear swaps before having to change the gasket.
DD

"Are you sure its not dripping down from the fill screw or pinion?"

The unit was completely rebuilt, Auburn Gear, etc. and was checked for cracks before reassembly, according to West Cost Differentials which did the work. Not that they could not make a mistake . . .

I don't see a crack. Just now looked it over with a magnifying glass.

"Are you sure its not dripping down from the fill screw or pinion?"

The drip seems to be only from the very bottom, at the point of contact between the carrier and the housing.

"Get the carrier spotless to see possible cracks."

It's clean, but painted. If there's a crack, the paint shouldn't hide the oil pathway, I would think.

Thanks Pierre & Doctor Dodge. I'll put a flat file on it tomorrow and apply the recommended silicon.

--Walt Jackson

Nine times out of ten the fluid walks past the threads of the studs.
clean the area completely with carb cleaner spray and allow to dry.
make sure that the dab of sealer goes completely around each stud.
if you can, wait over night before adding the gear oil.