I happen to have a couple of quarts of Mobil 1 75w-90 LS differential fluid in the garage. I saw on another post that "LS" is not needed if I have the AAM axle. I have the AAM with a 3.73 ratio. Not sure if it is the 11.25 or something else though. Can I use this? Does it really cause any problems or should I go buy 4 new quarts of regular 75w-90 synthetic gear oil. Thanks for any replies.

 

I am pretty sure it should be synthetic. If you pull trailers alot they suggest you run 75-140 wt. synthetic. This is what I run in mine.

 

It will cause no problems. Some people add LSD additive anyway. The say it helps stop the chatter some folks get when everything get's hot during a heavy pull.

 

In our town that is all that you can find. The guys at the counter sell it to Dodge guys all day long. Mine took 5 and a half quarts

 

Thanks for the input. You are right 1-2-3. I checked and all the part stores around here only sell the LS type also. I bought a couple more quarts and will put it in tomorrow. I also learned from this site that I have the AAM 11.5 differential. This forum is great

 

Don't over torque the bolts or they will break. 25 ft/lbs is all you need. Gasket is reusable.

 

That's all I use on my 06 works just fine 130k on her, I do have a maghytec cover on my rear diff so it does take more, but works great.