2011 Ram 1500 Differential and Transfer Case

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Mar 7, 2005
Greenville, SC
Can someone recommend a really good oil for the front and rear limited slip diff and also for the transfer case on my Ram 1500? 75w-140 rear 75w-90 front. Transfer case (NV243) calls for atf+4.

Looking, or should I say, dreaming for something that might show some efficiency gains in mpg. My common sense says to wish in one hand and [censored] in the other and see which one fills up faster LOL

My initial thoughts were Royal Purple, but I am open to suggestions.
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Doubtful if you can save enough fuel to cover the extra cost of a premium gear oil. The ATF+4 products will all be more alike than different in this regard.

What gear oil would best protect the differential in your driving conditions including weather? Use that one.
If I were to spend extra $ for premium gear oils, I would spend it on Redline products. As far as improved fuel efficiency, I do not believe there is more than 1 or 2% to be gained. But my experience with Redline MTL and 75w/90 gear oils in transmissions and transfer cases is that they mostly come out looking like they went in, even after 70k+ miles.
Premium gear oils are already required.

Transfer case: Any full synthetic ATF is an option. Some brands of ATF+4 are labelled full synthetic.

Front diff...any full synthetic GL5 75w90. Consider 75w85 only if vehicle is not worked.

Rear diff...any full synthetic GL5 75w140. Consider 75w110 if there is no towing/working.

Full synthetic steering and transmission fluids can be used too.
ATF+4 (for your transfer case) is a very, very tight spec. Avoid store brands that "meet or exceed" and use only brand names that are marked ATF-4 Certified.

Besides being tight it is a very good spec, and there is no real advantage to buying any one or another brand. The only thing botique brands can offer you is non-certification.


I'm not saying non-certified botique brands will grenade your transfer case, just that there is really no advantage to them at all.
Go with Royal Purple. I did and never looked back. It seems to be outstanding quality gear oil. $19.99/quart at Autozone, and 14.99/quart for ATF at Oreilly's. And dont forget about to add the Mopar Friction modifier (like 8 bucks at the stealership.) A lot of gear lubes say they already contain it, but I have always found they chirp like crazy unless you add some supplemental modifier
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