The rear diff cover on my '98 OBW is covered with oil. I intent to check the diff oil level this weekend (and probably just go ahead and change the fluid again). No, I do not hear any screeching noises coming from the rear diff, so there must still be oil in it.

 

I changed the diff oil last year. I did not put any sealant on the diff plugs. I wonder if that caused some of the diff oil to leak out.

 

Is sealant recommended? If so, can anyone recommend a type or brand?

 

Does anyone else have this problem? Could the diff oil be coming out of a vent hole somewhere on the top of the diff? I don't think that the gasket behind the diff cover is the reason, but I'll give it a closer look this weekend.

I had a similar problem and it turned out that I hadn't tightened the plug enough. I tightened it a little more and the leak stopped. Maybe someone here knows what torque it should be tightened to...now that I own a torque wrench.

i think its a tapered pipe thread, so being loose would make it leak. they gotta be very tight. but teflon tape, or pipe dope (sealant white stuff) should work great.

Earlier this year I changed the diff fluid on my wife's '03 H6 Sedan, and I noticed that the factory had used some sort of black sealant around the diff plugs. There was still some on the plugs when I reinstalled them. The rear diff on her car is not leaking.

 

Does anyone know what that black compound on the diff plugs is? It has to be some sort of sealant.

i think the air vent tends to get clogged and then leak. mine has been doing the same for about 10k miles. but i've cracked the fill plug and checked it every couple thousand or so and haven't seen a noticable drop. a little bit of oil leaking can make a really big mess...

 

as for the recommended sealant, here is what subaru recommends for a bunch of different applications. i used some permatex 599 the first time (ultra gray), and haven't used any on the recent times i have checked it. i think if it is tight enough, it doesn't leak at all. torque spec for a 97 is 32 ft-lbs.

 

The Other Skip: Thanks for your post. That's the info I was looking for.

To theotherskip: Thank you!!!

I had the same experience as Strakes. Very wet rear diff which was cured by another quarter turn in on the drain plug.

I would be very carerful using sealant on those plugs, you don't want to contaminate the gear lube.

 

I have never had a leak, I just torque it to spec and coat the outside with never sieze.

I used Permatex thead sealer with teflon. It's a thick paste that won't creap past the threads into the diff oil.

 

A little bit goes a long way.