2023 Ram 3500 Complete Fluid Specs & Capacities

As an ASE-certified master technician, I can tell you that the 2023 Ram 3500 is a workhorse engineered to haul, tow, and endure. However, whether your rig is powered by the 6.4L HEMI V8 or the legendary 6.7L Cummins Turbo Diesel (Standard or High Output), its longevity relies heavily on strict adherence to factory fluid specifications. Heavy-duty trucks generate extreme heat and shear forces, meaning generic fluids will lead to accelerated wear and catastrophic failure.

Below is the complete, factory-spec fluid guide for the 2023 Ram 3500. Always verify exact capacities in your owner’s manual or OEM service info, as they can vary slightly by cab configuration, cooling package, and exact axle combination.

Quick reference

Fluid	Type/Spec	Capacity
Engine Oil (6.4L HEMI V8)	0W-40 Full Synthetic, API SP (Mopar MS-12633)	7.0 qts (6.6L) with filter
Engine Oil (6.7L Cummins)	10W-30 or 5W-40 Synthetic, API CK-4 (Cummins CES 20086)	12.0 qts (11.4L) with filter
Engine Coolant	Mopar 10-Year/150,000 Mile OAT (MS-90032)	16.6 qts (6.4L) to 29.5 qts (6.7L)
Transmission (6.4L - 8HP75)	Mopar ZF 8 & 9 Speed ATF	Fill to spill (approx 9 qts dry)
Transmission (6.7L Std - 68RFE)	Mopar ATF+4 (MS-9602)	5.5 - 6.5 qts (pan drop)
Transmission (6.7L HO - Aisin AS69RC)	Mopar Aisin AS68RC/AS69RC ATF	7.2 qts (pan drop)
Transfer Case (4WD)	Mopar BW44-44 Transfer Case Fluid or ATF+4 (Verify unit)	Approx 2.0 qts
Front Differential	75W-85 or 75W-90 Synthetic GL-5	Approx 2.3 qts
Rear Differential	75W-140 Synthetic GL-5 (MS-8985)	Approx 4.0 - 4.2 qts
Brake Fluid	Mopar DOT 3 (MS-310)	Fill to MAX line
Power Steering Fluid	Mopar ATF+4 (MS-9602)	Fill to MAX line
Diesel Exhaust Fluid (DEF)	API Certified ISO 22241	5.7 gallons
Windshield Washer Fluid	Standard all-season fluid	1 gallon

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Engine Oil

6.4L HEMI V8

For the gas-powered V8, Ram requires a 0W-40 full synthetic engine oil meeting API SP standards and Chrysler material standard MS-12633. Pennzoil Ultra Platinum is the factory fill and highly recommended. Interval: The oil life monitor will dictate changes, but never exceed 10,000 miles or 12 months. Pitfalls: Do not substitute 5W-20 or 5W-30. The 6.4L engine runs hot and requires the robust film thickness of a 40-weight oil to protect the variable valve timing (VVT) components and cam lobes.

6.7L Cummins Turbo Diesel

The Cummins diesel demands heavy-duty engine oil meeting API CK-4 and Cummins CES 20086. Ram recommends 10W-30 for temperatures above 0°F (-18°C), but for year-round protection, towing, or colder climates, a 5W-40 full synthetic (like Valvoline Premium Blue) is preferred. Interval: Driven by the duty cycle monitor, but strictly not to exceed 15,000 miles, 500 hours, or 12 months. (Severe duty towing requires 5,000-7,500 mile intervals). Pitfalls: Never use API FA-4 oil in this engine, as it is a lower high-temperature high-shear (HTHS) viscosity oil that will cause bearing wear in a Cummins.

Engine Coolant

Both gas and diesel Ram 3500s require Mopar 10-Year/150,000 Mile Formula OAT (Organic Additive Technology) coolant, spec MS-90032. It is typically purple/pink in color. Interval: Flush and fill at 150,000 miles or 10 years, whichever comes first. Pitfalls: Never mix OAT with HOAT (Hybrid Organic Additive Technology). Mixing coolant types will cause the corrosion inhibitors to drop out of suspension, forming a thick, muddy gel that clogs the heater core, radiator, and engine block coolant passages. Always dilute concentrated coolant with distilled water, never tap water.

Transmission Fluid

There are three distinct transmissions available for the 2023 Ram 3500, and they do not share fluid requirements. Never use a "universal multi-vehicle ATF" in these specialized gearboxes.

1. 8HP75-LCV (6.4L Gas): Requires Mopar ZF 8 & 9 Speed ATF. This is a highly specialized, low-viscosity fluid.
2. 68RFE (6.7L Standard Output): Strictly requires Mopar ATF+4 (MS-9602).
3. Aisin AS69RC (6.7L High Output): Requires Mopar Aisin AS68RC/AS69RC ATF (Mobil Delvac 1 ATF is also an approved equivalent). Interval: For severe duty (frequent towing, hauling), the 68RFE and Aisin transmissions require fluid and filter changes every 30,000 miles.

Transfer Case Fluid

Four-wheel-drive models utilize BorgWarner transfer cases. Check your specific RPO codes or the tag on the back of the case. Most require Mopar BorgWarner Transfer Case Fluid (often labeled for BW44-44/BW44-46). Some configurations may specify ATF+4. Interval: Replace every 30,000 miles under severe duty/towing conditions.

Differential Gear Oil (Front & Rear)

Ram heavy-duty axles require robust GL-5 gear lubricants.

• Front Axle: 75W-85 or 75W-90 fully synthetic GL-5 gear oil.
• Rear Axle: 75W-140 fully synthetic GL-5 gear oil. If your Ram is equipped with an anti-spin (Limited Slip) rear differential, a friction modifier additive (Mopar MS-10111) is usually required to prevent clutch chatter, though many premium synthetic 75W-140 fluids contain it pre-mixed. Interval: Check every 20,000 miles. Replace every 30,000 to 40,000 miles if towing frequently.

Brake Fluid

Use Mopar DOT 3 Brake Fluid (MS-310). Interval: Brake fluid is hygroscopic (absorbs moisture from the air). Test for moisture content annually, and flush the system every 2 to 3 years to prevent internal corrosion of ABS module valves and calipers.

Power Steering Fluid

Unlike lighter trucks that have moved to Electric Power Steering (EPS), the 2023 Ram 3500 heavy-duty steering gear utilizes hydraulic assist. It requires Mopar ATF+4 (MS-9602). Pitfalls: Do not use generic clear "power steering fluid." The specific friction modifiers and anti-foaming agents in ATF+4 are required to keep the pump quiet and preserve the steering gear seals.

Diesel Exhaust Fluid (DEF)

For Cummins-equipped models, you must use DEF that meets ISO 22241 specifications and is API Certified. Interval: Top off as indicated by the DEF gauge. Pitfalls: DEF degrades when exposed to extreme heat or sunlight. If you buy DEF in jugs, check the date code. Bad DEF or crystallization will quickly trigger a derate condition and throw SCR/NOx sensor faults.

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