Sorting out all of the bugs...now the REAR END

RichieRich · Feb 26, 2013

Well, I'm getting the bugs all sorted out on the new to me 7.3 F250 I picked up...now I need to address the leaking differentials. It seems easy enough, I just want to be sure to use the right fluid. Can I run straight synthetic or do I need to run some type of additive for limited slip? I would love to do the finned rear end cover, but I'm not spending money on that stuff right now. Thanks in advance for the help I'm sure you'll give me!:rockon:

kluttzstroker · Feb 26, 2013

It really don't matter but I used 90/140 rearend oil

bluedevilslax · Feb 26, 2013

I personally, have never added a friction modifier to the rear end. I have just run full synthetic. And if you are looking for a finned reared that 08 diff cover can be put on your rear end and you can get that from the Ford dealer for a pretty reasonable price.

Hope this helps but I will let others chime in as well.

MossBack · Feb 26, 2013

Look up the sponsors here that make the site run. I think I spent like 60 at my dealer on a parts account and it is cheaper on here through sponsors. If u go the route of the cover don't buy the bolts from the dealer. 5/16x20 x 1-1/4 bolts.

And not all synthetic is created equally. Some have more friction modifiers in them. When u change the oil and it chatters around corners that is the sign some additive is needed.

RichieRich · Feb 26, 2013

Cool...I was thinking of just picking up 7 quarts of the Mobil 1 stuff from Pep-Boys....does anyone know the torque specs on the diff cover bolts? Also I was going to use Black Silicone, that should work right?

PDT1081 · Feb 26, 2013

RichieRich said:
Cool...I was thinking of just picking up 7 quarts of the Mobil 1 stuff from Pep-Boys....does anyone know the torque specs on the diff cover bolts? Also I was going to use Black Silicone, that should work right?

I used high temp RTV (orange). Lay a bead around the flange, make sure to go around each bolt. SNUG the bolts by hand and let it sit for a few hours, then tighten the rest of the way. I've never used a torque wrench on a diff cover and mine does not leak. I've done quite a few Dana 60's and none of those have leaked either.