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Our Wildwood, FL techs will confirm the right part for your build before you buy.
Call or Text (352) 722-5295Differential fluid for the 1994-1998 Ram 5.9L Cummins
A 4x4 second-gen Ram with the 5.9L Cummins has two differentials to fill: the Dana 60 front, and either a Dana 70 or a Dana 80 in the rear. A 2WD truck has only the rear. If the Dana 80 has a limited slip, it's a Power Lok through 1997 or a four-pinion Trac Lok from 1998, so read each oil's label for limited-slip use before you pour.
What we carry
- Hot Shot's Secret Adrenaline synthetic racing gear oil in 75W-90, 80W-110 and 85W-140
- Hot Shot's Secret Blue Diamond HD synthetic gear oil in 75W-90, 80W-110 and 85W-140
- Lucas Oil Synthetic 75W-90 and 75W-140, plus Heavy Duty 80W-90 and 85W-140
- Royal Purple Max-Gear 75W-140 synthetic gear oil
Choosing a gear oil
Start with the viscosity your axle's service information calls for, then pick the product. The range here runs from 75W-90 up to 85W-140, across synthetic and heavy-duty lines. If you've installed a finned aluminum cover, plan on extra oil: those covers add fluid capacity, and the Mag-Hytec style carries a dipstick so you can fill to the right level without guessing.
Fitment notes
Gear oil isn't year-specific, but your axles are. Confirm Dana 70 or Dana 80 from the axle tag, since a 2500 automatic and a 2500 manual use different rear axles. The NV4500 manual transmission is a separate fill with its own fluid spec, so check before you top it off from the same bottle.
Frequently asked questions
Does my gear oil need to be limited-slip compatible?
If your rear axle has a limited slip, check before you buy. Dana 80 trucks used a Power Lok through 1997 and a four-pinion Trac Lok from 1998. Read each product's label for limited-slip use, or call us with your axle tag info.
Should I run synthetic gear oil in my Dana axles?
Most of what's here is synthetic: Hot Shot's Secret Adrenaline and Blue Diamond, Lucas Oil Synthetic and Royal Purple Max-Gear. Lucas Oil Heavy Duty grades are here too. Get the viscosity right for your axle first, then choose the product.
Not sure what fits? Call the shop at the number in the header, or use the fitment checker on any product page. We install everything we sell.