I have a '05 Ram 2500, I want to change the Differential Fluid. I was just in the parts store they had Mobil 1 Full Synthetic 75w 90. (on the front label it said LS) But on the back label it said meets GL-5. Is this good for my truck.

 

Yes, it good. LS is special additive to GL-5 spec fluid. If has the AAM(?, not the Dana 70-80) axle it not need LS. Check again

 

I have been running Mobil 1 75w90 GL-5 synthetic gear oil in my diffs for the past 110K miles with no problems. Good stuff. I change out every 20K miles now...which is probably overkill.

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The Mobil1 is a bargain compared to the others right now. I've seen Royal Purple for as much as $19.99. When I used it, 20,000 miles ago, I think I paid $11. I won't buy it next time, not at those prices, and will most likely give Mobil1 a try.

 

I use Redline myself, and order it through JEGS.

 

is mobile 1 good for the tranny also

 

mobile 1 here to. but i go 30,000 on changes in the rear. with the mag. still doing the front at 15,000. untell i get a mag up there

 

If you have the G56 it calls for atf+4 synthetic. Don't know about the previous manuals.