Diff fluid change
 

My wifes durango has about 150,000 miles on it. I want to change the rear end fluid. What are you guys using and how many bottles does it take. I was thinking of using some kind of synthetic 80w-90 with one bottle of mopar friction modifier. what do you guys think?

KD:

Most of us run one of the better synthetics such as Mobil 1, Amsoil, or Royal Purple.

You can run the 80/90, or the 75/140 if you tow alot.

I went with M1 at my 30k, and when I pulled it at 60k it still looked and smelled like new.

The OEM dino crap that came out at 30k looked and smelled like dino poop.

I went back in with Royal Purple at 60k, and so far so good.

Don

so do i need mopar friction modifier, or just new 80/90? and how much does it take?

KD:

You only need the friction modifier if your rear axle has the limited slip carrier. Both Mobil 1 and Royal purple say that it should not be needed if you use them.

Some folks have found that to be true, and others have had noises that went away after adding the modifier.

IIRC, it comes on a 4-6 ounce bottle which is enough to treat one axle.

My D does not have the LS option, and when it was part time 4x4 I considered adding an LS carrier. After thinking a bit more, I realized I could make the swap to AWD for about the same price, and decided to do that instead.

Don

cool, so how many quarts of gear oil should i buy?

I don't mean to jack the thread but how do you tell if you have an LSD? I have a 2002 SXT. I'm also contemplating on changing my rear diff fluid.

KD:

You will need at least two for either the front or back, so if you get three you can do them both.

Mshark:

Check your glove box for a sticker in there on the inside bottom that should list several options on your D.

Where it talks about axles, it will say the size for the rear (either 8.25 or 9.25), and then the words Anti-Spin if you have the LS.

A second location to verify is a white label behind your driver side rear wheel on the axle tube. It Should give the ratio (3.55 or 3.92), then say Anti-Spin or Open Carrier if not equipped.

Don

They are all Limited Slip on the rear as far as I know.

Yes you need the friction modifier.

The best use of gear oil in my opinion is 80/90 full sythetic. Go to the dealer and get the friction modifier because I'm sure it's sythetic.

I never used the modifier with the Mobil 1 and I've been fine. IIRC it was a little more than 2 quarts per diff.

What are? Durangos? That would be a big negative. Not all are LS. Mine is not.