Which gasket is leaking?

[kuranes]

Forum and truck newbie here, sorry if this is a basic question. I bought a 1995 6.5L diesel Suburban last year as a project. Life intervened and kept me from working on it much, but now I'm back at it. I want to replace the rear diff fluid and gasket. When I looked at the diff, I noticed that there's oil on one side of it, where the axle goes into the differential.

It seems like maybe this isn't leaking from the diff cover gasket, but from another seal. Any thoughts or insight?

Pic:

 

[WarWagon]

This is the housing tube to center pumpkin that is leaking. (Seeping really.) Ignore it or swap out the complete rear axle.

 

[schiker]

Might be the filler plug is seeping a bit and getting blown back on that side slowly and dirt kind of wicks it around. On refill maybe put a little thread sealer on the fill plug. Mine around the fill plug is grimy from similar seepage but not really on back side of axle. Very could well be axle tube.

 

[ak diesel driver]

I was wondering about a pinhole in the brake line.......

 

[Will L.]

A little bit of degreaser or dawn dish soap will help here. Clean it off. Pull the cover and change the fluid. Clean the making surfaces well and no gasket- by a tube of permatex "the right stuff". It seals better than any diff gasket will.

Drive and play with other parts of the truck, just remember to watch for a seep to start. Check daily for the first week. Make sure it is not the brake line- if so stop driving and replace immediately. If it is an axle tube (also my guess) and it really bothers you and swapping the axle is too much$, a little brazing job will do it just fine- there once was a 77 srw 3500 I had that got just such a treatment.

 

[3500GMC]

Was gonna mention the vent but the 9.5 is connected to a hose fastened to the underside of the body/bed. Err I think..