2020 Ram 1500: Transmission Fluid & Service

Quick answer

• Transmission: ZF 8HP75 8-Speed Automatic (Sales Code DFR)
• OEM Fluid Specification: Mopar ZF 8&9 Speed ATF (Spec MS-90709-AA)
• Fluid Part Number: 68218925AB (quart), 68218926AB (gallon)
• Drain & Fill Capacity: Approximately 5.5 - 6.0 quarts (verify by checking level)
• Full Overhaul Capacity: 9.0 quarts (9.5 liters)
• Filter Part Number: 68417772AA (Integrated filter/pan assembly)
• Recommended Service Interval: 60,000 miles (severe duty) to 100,000 miles (normal duty)

Fluid type explained

The 2020 Ram 1500 with the 8-speed automatic uses a specific, high-performance synthetic fluid called Mopar ZF 8&9 Speed ATF. The official Stellantis (formerly FCA) material specification is MS-90709-AA.

This is not a traditional ATF+4 or generic multi-vehicle fluid. The ZF 8HP series transmissions are sophisticated units that require a fluid with a precise viscosity, friction modifier package, and additive composition to ensure smooth shifting, proper torque converter lock-up, and long-term durability of the internal clutches and mechatronics. Using a non-approved fluid can lead to shift quality issues, accelerated wear, and potential transmission failure. Always insist on a fluid that explicitly meets the MS-90709-AA specification.

Service procedure

Servicing the ZF 8HP75 transmission is different from older designs. The transmission oil pan is a polymer composite material and has the fluid filter integrated directly into it. Therefore, a standard "filter change" requires replacing the entire pan assembly.

• Drain & Fill: This is the most common service procedure. It involves draining the old fluid from the transmission pan's drain plug, replacing the pan/filter assembly with a new one, and refilling the transmission with new fluid. This typically replaces around 5.5 to 6.0 quarts of the total fluid.

• Fluid Exchange (Flush): A full fluid exchange uses a specialized machine to pump out all of the old fluid from the pan, cooler lines, and torque converter while simultaneously refilling with new fluid. This method replaces nearly 100% of the old fluid but is more expensive and not always necessary. For the ZF 8HP, a proper drain, pan/filter replacement, and refill is the manufacturer-recommended procedure.

The fill procedure is critical. The transmission has no dipstick. The fluid level must be checked via a fill plug on the side of the transmission case while the engine is running and the transmission fluid is within a specific temperature range (typically 30-50°C or 86-122°F). The level is correct when fluid begins to drip slowly from the fill port. This process requires a scan tool to monitor transmission fluid temperature and should be performed by a qualified technician.

Service interval

Ram provides two primary service intervals for the 8-speed automatic transmission.

• Normal Duty: For vehicles that see primarily highway driving in moderate climates with little to no towing, Stellantis considers the fluid to be "fill-for-life." However, most independent specialists and ZF themselves recommend a service interval of 8 years or 100,000 miles to ensure maximum longevity.

• Severe Duty: This is the more realistic interval for most truck owners. If you frequently tow trailers, haul heavy loads, operate in dusty or off-road conditions, idle for long periods (e.g., job site work), or drive in mountainous terrain or extreme temperatures, your truck falls under the severe duty category. The recommended service interval is 60,000 miles.

Common transmission problems

The ZF 8HP series is widely regarded as a robust and reliable transmission, but some common issues have been noted:

• Harsh Shifting When Cold: Some owners report firm or delayed shifts for the first few minutes of driving in cold weather. This is often considered normal as the fluid warms up and the transmission adapts.

• Shift Quality Complaints: Occasional reports of rough 2-1 downshifts or "shuddering" during light acceleration can occur. Often, a software update to the Transmission Control Module (TCM) from a Ram dealer can resolve these issues by refining the shift logic.

• Fluid Leaks: While not rampant, leaks can develop over time from the pan gasket, electrical connector sleeve, or cooler lines. The composite pan, if over-torqued, can also be a source of leaks.

• Mechatronic Unit Issues: In higher-mileage examples, internal solenoids or sensors within the mechatronic (valve body) unit can fail, leading to shift faults and trouble codes. This is uncommon but can be an expensive repair.

Regularly servicing your transmission with the correct fluid and filter is the most effective way to prevent these issues and ensure a long service life.

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