2019 Ram 2500 Fluid Type Specifications & Capacities

As an ASE-certified master technician, I can tell you that the 2019 Ram 2500 is an absolute beast of a workhorse. Whether you are running the 6.4L Hemi V8 or the legendary 6.7L Cummins Turbo Diesel (Standard or High Output), maintaining these heavy-duty trucks requires strict adherence to factory fluid specifications. Using the wrong fluid—especially in the complex Aisin transmissions or the emissions-controlled Cummins—can lead to catastrophic failures and voided warranties.

Below is your complete guide to the factory-spec fluids for the 2019 Ram 2500.

Quick reference

Fluid	Type/Spec	Capacity
Engine Oil (6.4L Hemi V8)	0W-40 Full Synthetic (MS-12633 or MS-10725)	7.0 qts (6.6 L)
Engine Oil (6.7L Cummins)	10W-30 or 5W-40 Synthetic (API CK-4, CES 20086)	12.0 qts (11.4 L)
Engine Coolant	OAT 10-Year/150k-Mile (MS-90032), Purple/Pink	16.6 qts (Gas) / 21.2+ qts (Diesel)
Transmission (8-Spd Hemi)	Mopar ZF 8&9 Speed ATF	Verify in owner's manual
Transmission (68RFE Diesel)	Mopar ATF+4 (MS-9602)	Verify in owner's manual
Transmission (Aisin Diesel)	Mopar ASRC / Aisin AW-4	Verify in owner's manual
Transfer Case (4WD)	Mopar BW44-44 Fluid or ATF+4 (Verify exact unit)	~2.0 qts
Front Differential	75W-85 or 75W-90 GL-5 Synthetic	~2.5 qts
Rear Differential	75W-140 GL-5 Synthetic (+ Friction Modifier if LSD)	~4.2 - 4.5 qts
Brake Fluid	Mopar DOT 3 (MS-31)	Fill to MAX line
Power Steering Fluid	Mopar Power Steering Fluid +4 (MS-9602)	Fill to MAX line
Diesel Exhaust Fluid (DEF)	API Certified / ISO 22241	5.7 gallons
Washer Fluid	Standard All-Season Windshield Washer Fluid	Fill to MAX line

Note: Capacities are approximate dry fill/service fill estimates. Always verify in owner's manual / OEM service info and check the dipstick or fill hole level after servicing.

Engine Oil

For the 6.4L Hemi V8, Chrysler specifies a 0W-40 full synthetic engine oil that meets Mopar MS-12633 or MS-10725 standards. The Hemi's Multi-Displacement System (MDS) relies on precise oil pressure to activate and deactivate cylinders, so do not substitute weights.

For the 6.7L Cummins, the specification is API CK-4, Cummins CES 20086. Standard operating temperatures call for 10W-30, but if you operate in cold climates (below 0°F) or want superior protection for heavy towing, a 5W-40 full synthetic is highly recommended. Common Pitfall: Never use old CJ-4 stock on a 2019 Cummins, as the newer CK-4 spec is required for the updated emissions equipment. Change intervals vary by duty cycle, but typically max out at 15,000 miles or 500 hours—whichever comes first. Don't push it if you tow heavy.

Engine Coolant

The 2019 Ram 2500 uses Organic Additive Technology (OAT) coolant, designated by Mopar MS-90032. It is typically purple or pink in color. Common Pitfall: Never, under any circumstances, mix this OAT coolant with the older orange Hybrid Organic Additive Technology (HOAT) coolant used in pre-2013 Rams, or with "universal" green coolants. Mixing OAT and HOAT creates a gel-like sludge that will quickly clog your heater core, radiator, and engine water jackets. Service interval is 10 years or 150,000 miles, but I recommend testing the freeze point and pH every 50,000 miles.

Transmission Fluid

This is where the 2019 Ram 2500 gets complicated, as there are three different transmissions available:

1. 8HP75 8-Speed Automatic (6.4L Hemi): Requires Mopar ZF 8&9 Speed ATF. Do not use ATF+4 in the ZF transmission.
2. 68RFE 6-Speed Automatic (Standard Output 6.7L): Strictly requires Mopar ATF+4 (MS-9602). Universal ATFs can cause shudder and premature clutch wear.
3. Aisin AS69RC 6-Speed Automatic (High Output 6.7L): Requires Mopar ASRC (Aisin Specific) fluid. Do NOT put ATF+4 in the Aisin; it will slip and fail.

Service intervals on these transmissions vary wildly. The Aisin typically requires fluid and filter changes every 30,000 miles under severe duty, while the ZF claims to be "filled for life" (though as a tech, I recommend servicing the ZF every 60,000 miles).

Transfer Case

Four-wheel-drive models utilize BorgWarner transfer cases. Depending on your exact build (electronic vs. manual shift), it requires either Mopar Transfer Case Fluid BW44-44 or ATF+4. You must verify the specific fluid tag on the back of the transfercase or check your VIN through a dealer. Using the wrong friction modifiers in the transfer case can cause binding or chattering in 4x4 mode.

Front and Rear Differentials

Ram heavy-duty trucks utilize massive AAM (American Axle & Manufacturing) axles.

• Front Axle: 75W-85 GL-5 synthetic gear lubricant. (75W-90 is often an acceptable aftermarket substitute if 75W-85 is unavailable, provided it meets GL-5).
• Rear Axle: 75W-140 GL-5 full synthetic gear lubricant.

Note on Limited Slip: If your truck is equipped with the anti-spin rear differential, you must ensure your gear oil contains a friction modifier additive. Many premium synthetic gear oils include this off the shelf, but if yours does not, you will need to add a small bottle of Mopar Limited Slip Additive (MS-10111) to prevent the clutch packs from chattering around tight corners. Change diff fluids every 20,000 to 30,000 miles if you tow frequently.

Brake Fluid

Ram specifies DOT 3 brake fluid (Mopar MS-31) for the 2019 2500, though high-quality DOT 4 can be used as it is backwards compatible and offers a higher boiling point—great for heavy towing. Never use DOT 5 (silicone-based) fluid, as it will destroy the seals in your ABS module. Brake fluid is hygroscopic (absorbs moisture), so flush the system every 2 years or 30,000 miles.

Power Steering Fluid

The heavy-duty steering box on the 2019 Ram 2500 utilizes hydraulic pressure. You must use Mopar Power Steering Fluid +4, which is effectively the same formulation as ATF+4 (MS-9602). Avoid generic "power steering fluid" from auto parts stores, as it lacks the proper anti-foaming agents required for the Ram's steering pump and hydro-boost braking system (if equipped).

Washer Fluid

Any standard all-season windshield washer fluid will work. In colder climates, ensure it is rated for -20°F or lower to prevent the reservoir and lines from freezing and cracking.

Diesel Exhaust Fluid (DEF)

For Cummins models, you must use Diesel Exhaust Fluid that meets ISO 22241 and is API certified. DEF is 32.5% high-purity urea and 67.5% deionized water. Common Pitfall: DEF degrades quickly in heat and sunlight. Never buy DEF that has been sitting outside a gas station all summer, and avoid buying more than you can use within a few months. Contaminated or expired DEF will trigger a "Service DEF System" warning, potentially derating the engine to a 5-mph crawl until the tank is drained and the system is recalibrated.

Maintaining a 2019 Ram 2500 isn't cheap, but using the exact factory-specified fluids is far less expensive than replacing an Aisin transmission or a Cummins SCR system.

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