Very good point here, I would try this prior to pulling your cover off again, and also keep in mind that depending on the quality of the aluminum, it is much more prone to flex which will in-turn cause loose bolts. The RTV will also act as a loc-tite, helping to keep the bolts in place. Time & Money saved!

 

Maybe not a total hijack, but a slightly different direction on the same topic...

When I recently purchased my 04 2wd 6.0 excursion, the previous owner had a dealership replace the pinion seal and flange under ESP when I noticed some oil slung around.

Fast forward two months and 7000 miles.

I begin to hear a noise, very much like mudder tires on pavement, not real loud, the radio needs to be off to hear it. I assume it's the very old tires, showing wear bars, and replace them.

The noise remains. The noise does not change in coasting down in nuetral with the engine off, with the engine on, the brakes applied or not.

It is loudest at about 30 mph while coasting down, definately related to wheelspeed, so that brought me to the rearend.

No leaks found under inspection, the pinion area does look like it was serviced, so I check the fluid.

Pull the plug, stick my finger in, don't find oil until I touch a surface.

The oil looks good, smells not so good, a light burnt smell.

I top off the diff with mobil 1 75W140 synthetic (only choice in that weight at the local parts store), 28 oz (almost a full quart) are required to top off the diff.

The fill plug appeared to have a thick grey grease coating on the inside surface, much like silver colored anti-sieze and just about as messy. "thick" means at least 3/16" thick, appeared to be placed there on purpose as there was none inside the case.

Test drove after refilling, the noise remains, no worse, no less.

Pinion bearing? It wasn't replaced two months ago.
Clutches making noise? Are there clutches in the rear diff?

Opinions and advice welcome....

 

Drain the oil, remove the drive shaft and drive it in 4 wheel drive. Then you will have a FWD. Problem solved!

 

Never liked using blue silicone where oil is present. I'd use a gasket, along with the orange silicone. Some blue I'm sure is fine when used around oil, but some of it is only for water locations like thermostat housings. Also, make sure the breather vent is clear. After assembly, give it an hour or so before filling it up.

 

The silver greasy coating on your drain plug is metal. That plug is a magnet. Sounds like you have a problem,Either a new ring and pinion or bearings to solve it, Take it back to your dealer

 

Actually the gasket that comes in the master rebuild kit doesn't offer a very good seal. When I regeared mine the fella used the gasket. Two days later I was back in the shop having him put black RTV on it. As it leaked somethin' fierce.

There's a nice little channel all the way around that diff cover for the RTV. I agree, it sounds as if either the guy didn't use enough or didn't allow it to skin over.

I've not had any more issues with my 08 diff cover.

 

Monsta,

I actually thought about asking the shop to do it this way since they were having issues getting a good seal...especially since the '08 cover has that groove cut into the under side which would act like an O-ring after the RTV set up...

1) Remove cover and drain
2) Clean out housing very good and let drip over night (I was in no rush for the Ex)
3) Clean housing and cover of old RTV with proper solvent(s)
4) RTV the cover and make sure all bolt holes are covered properly
5) Install cover and torque to 1/8 to 1/4 bolt torque and let sit over night
6) Torque bolts rest of the way (24 ft-lbs)
7) Fill housing with 75W-140 Synthetic fluid

If I have to do this again...I believe this is how I will do it. This way the RTV will set up overnight...then I can compress it further filling any possible voids when I torque the bolts to 24 ft-lbs...

I haven't checked mine since I snugged the bolt...maybe tonight...

Just a thought...

Joe.

 

Try using Permatex Right Stuff gasket maker. Don't need to wait for it to cure, just squeeze, torque & refill. I've used it on diff covers, valve covers, thermostat housings, motor & tranny oil pans and water pumps. Haven't had a leak yet. (knock on wood)

 

Well I checked the cover last night. I snugger her up on Sunday afternoon...and so far so good...NO MORE LEAK...I'll continue to watch it but hopefully this fixed her.

Thanks again for all the advice...rep points all around!

Joe.