What differential fluid does a Ram 2500 take?

The manual's Chassis Fluids And Lubricants tables list the axle lubricant for each engine:

The 75W-140 Mopar GL-5 Synthetic Gear Lubricant listed in the diesel table is for the 3500's 12.0 in rear axle, not the Ram 2500.

From the 2026 Ram 2500/3500 owner's manual (Chassis Fluids And Lubricants, 6.4L gasoline and 6.7L diesel), read November 8, 2026.

Limited-slip differential additive

The manual says Limited-Slip Differentials DO REQUIRE limited slip oil additive (friction modifiers). For the 6.7L diesel it recommends the pre-mixed Mopar lubricant and limited slip additive, and if the axle fluid is not pre-mixed, Mopar MS-10111 Limited Slip Additive for the 11.5 in rear axle.

It also notes that slight noise and mild shuddering may be evident while turning a vehicle with a limited slip differential on concrete or dry pavement, and that these conditions should be considered normal operation of the limited slip differential.

From the 2026 Ram 2500/3500 owner's manual (Rear Axle And 4x4 Front Driving Axle, Lubricant Selection; Chassis Fluids And Lubricants), read November 8, 2026.

How to check the Ram 2500 differential fluid level

For normal service, periodic fluid level checks are not required. When the vehicle is serviced for other reasons, the exterior surfaces of the axle assembly should be inspected, and if gear oil leakage is suspected, the fluid level should be inspected with the vehicle in a level position. The manual's method is:

1. Park the vehicle on a level surface.
2. Take a piece of wire (or zip tie) and make a 90 degree bend two inches from the end of the wire.
3. Insert the wire into the fill plug hole and use it like a dipstick.
4. Remove the wire and measure from the 90 degree bend to the oil level.

From the 2026 Ram 2500/3500 owner's manual (Rear Axle And 4x4 Front Driving Axle, Fluid Level), read November 8, 2026. For the 2500 (non-Power Wagon) axles, the level should be 4/5 in plus or minus 1/4 in (20.3 mm plus or minus 6.4 mm) below the fill hole for the rear axle and 1/4 in plus or minus 1/4 in (6.4 mm plus or minus 6.4 mm) below the fill hole on the front axle. For the 2500 Power Wagon, it should be 1/4 in plus or minus 1/4 in (6.4 mm plus or minus 6.4 mm) below the fill hole on the 9.25 in front and 11.5 in rear axle.

How often to change Ram 2500 differential fluid

For drain and refill, the manual refers to the Maintenance Plan. Both plans list the same item: inspect the front and rear axle surfaces; if gear oil leakage is suspected, check the fluid level; and if using your vehicle for police, taxi, fleet, off-road or frequent trailer towing, change the axle fluid. How often it comes up depends on the engine:

6.4L gasoline: every 20,000 miles (32,000 km) or 2 years, whichever comes first.

6.7L diesel: every 22,500 miles (36,000 km) or 18 months, whichever comes first.

From the 2026 Ram 2500/3500 owner's manual (Maintenance Plan, 6.4L Gasoline Engine; Maintenance Plan, 6.7L Diesel Engine; Rear Axle And 4x4 Front Driving Axle, Drain And Refill), read November 8, 2026.

Water in the axle

The manual notes that the presence of water in the gear lubricant will result in corrosion and possible failure of differential components. Operation of the vehicle in water, as may be encountered in some off-highway types of service, will require draining and refilling the axle to avoid damage.

From the 2026 Ram 2500/3500 owner's manual (Rear Axle And 4x4 Front Driving Axle, Lubricant Selection), read November 8, 2026.

Ram 2500 service at Elgin CDJR

If your Ram 2500 tows often or goes off-road, our Ram service center can inspect the axles and change the differential fluid with the lubricant the manual calls for. Our service department is open Monday to Friday 7 a.m. to 7 p.m. and Saturday 7:30 a.m. to 4 p.m., and is closed Sunday. Elgin CDJR is at 1500 W. Lake St. in Streamwood. Get directions.