02 SLT 5.9L AWD 3.92 LSD

About 6 months ago I changed out my rear differential oil/friction modifier. I had a tough time getting a good seal around the cover, but finally got it to seal. Well, this afternoon I noticed a spot on my driveway... looks like it is leaking around the cover again. I used the red RTV last time to seal the cover. What do you guys like to use? I thought about trying the silicone based stuff that is marketed for thermostat housings. Bad idea??? Any thoughts...

 

I used the blue RTV and it seems to be holding 4 months later...

 

I always use RTV Copper for all my needs.




For it to seal fully you are supposed to clean the **** out of it with a solvent like brake cleaner or carb cleaner that doesn't leave any residue behind and ensure it is nice and clean on both mounting surfaces. I always clean the diff sides with a rag sprayed with the cleaner.

Then you put a line of about 1/16 inch wide RTV on the cover and I spread it with a finger to make a nice thin layer. Then I do the same on the diff side. Then I place the cover on and just bring the bolts in lightly tight in a torquing pattern. I then leave it for about 30 min and then torque the bolts to spec's. I leave it overnight with the plug out to cure.

Next day I put the entire bottle of friction modifier (7oz bottle avalible at Auto Zone for $4.99) in first then fill the remaining just to the about 1/8" from below the bottom of the fill plug so it doesn't overflow when it gets hot. I use Mobil 1 LS 75W-90 Full Synthetic. http://www.mobiloil.com/USA-English/..._75W-90LS.aspx

 

i use the RTV with Silicone. clean the **** out of everything i could on both inside and out i also painted mine both inside and out with high temp paint but that was because it was brand new and i wanted to make sure it lasted. i also clean the housing with a soft compound cleaner wheel with my grinder. (they do make cleaning tool for this applaction) i dont trust the additive from auto zone so ill spend the $12 at the dealer and i only use lucas 90w. i have been running that for almost 3 years and i just changed it again. and for the most part it was clean a little burnt but that to be expected with the way i drive and tow and make the truck work.

 

Hydra, I use the same oil and modifier as you. I also used a wire brush adapter for my drill to remove every last piece of old sealer. Then I used brake cleaner to clean the surfaces. I'm really surprised it decided to leak now. I'll try a different sealant.
I don't think I hit anything. I did pull a stalled Chevy off the road 2 days ago though (mopar pride, loved it!)

 

Well, I don't know about how good their friction modifier is over a different company, so I did one up on ya........I e-mailed them for their MSDS sheet concerting the only way to get it is by request. Here is a dealer log in page to get the info, however I don't have the credentials. Part number: Mopar 04318060AB

https://dealerconnect.chrysler.com/d...oller%2fPortal


I'm gunna get the facts before I make any "interpretation" of what is better than what.

 

I've trusted Mobil with my most important fluids they carry (Mobil 1 FS oil and Mobil 1 LS rear diff lube) since day one and no issues from either of them. I trust Mobil products with my life and I had an issue with Lucas one time so don't use them for anything.

For those concerning questions about my issue with Lucas, I used their fuel treatment twice and ended up having to replace 2 injectors due to being clogged because of it. I sent them in to be cleaned and they were 100% sure t was the Lucas garbage in my fuel tank.

Had to buy new injectors as they were beyond fixable and drop the tank and clean it out. They left a bad taste in my mouth with that so now I only use SeaFoam in my fuel tank and Mobil 1 in my oil pan.

I agree with you Hydra as I don't know who's friction modifier is better, but the way it stands with me, they're most likely about the same just more expensive.

 

If it just decides to leak now, the RTV you used is giving out. I've always used blue RTV for gasket making and never had any problems. Your wire brush on the drill shouldn't have caused any problems since it was fine for months.
Hydra nailed how to get a perfect seal on it, the trick is to apply the RTV to both surfaces and smooth the bead down with your finger, then just snug the bolts in, wait about a half hour for it to settle and tighten everything down to torque specs, and let it sit overnight to air out and finish. Perfect seal everytime.

 

For anyone wondering, the torque specs for the rear diff. cover bolts are 30 ft. lbs.

 

Can you believe this ****?