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Call or Text (352) 722-5295Differential fluid on the 2019-2024 RAM 6.7L Cummins
Four-wheel-drive trucks have two differentials to service. The AAM 9.25-inch front holds about 2.45 quarts. The rear is an AAM 11.5-inch on the 2500 and most 3500s and holds 3.8 to 4.5 quarts. The 3500 Max Tow uses the AAM 12.0-inch rear with a helical, clutchless limited slip. Under severe use, Ram's schedule calls for differential service every 20,000 miles.
Choosing a grade
The first number in a gear oil grade describes cold flow and the second describes thickness at operating temperature. This page carries 75W-90, 80W-90, 80W-110, 75W-140 and 85W-140. None of them is the factory 75W-85, so check the oil's published specifications and your owner's manual before switching, and make sure the label covers limited-slip use if your truck has a limited-slip rear. Buy enough for both axles if you're servicing a 4x4. A front axle that keeps losing fluid after ball joint work usually needs new axle-shaft seals, not just a top-off.
What we carry
Hot Shot's Secret offers ADRENALINE racing gear oil and Blue Diamond HD synthetic gear oil, each in 75W-90, 80W-110 and 85W-140. Lucas Oil covers Synthetic 75W-90 (10047) and 75W-140 (10121), plus Heavy Duty 80W-90 (10043) and 85W-140 (10042). Royal Purple rounds it out with Max-Gear 75W-140 synthetic (01301).
Frequently asked questions
What gear oil came in my 2019-2024 Ram Cummins axles?
SAE 75W-85 GL-5 full synthetic, in both the front and rear. If you switch to a different grade, confirm it against your owner's manual and the oil's specifications first.
How often should I change the differential fluid?
Under severe use, every 20,000 miles. If your driving does not fall under the severe schedule, your owner's manual lists the normal interval. Any time a cover comes off for a gasket or an aftermarket cover, refill with fresh oil.
How much do I need to service both axles?
Plan on about 2.45 quarts for the front 9.25 and 3.8 to 4.5 quarts for the rear 11.5. Buy a little extra to cover what stays in the bottle and any spill.
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.