2026 Ram 2500 Maintenance Schedule
6.7L Cummins Diesel Guide
Owning a 2026 Ram 2500 with the 6.7L Cummins® Turbo Diesel is a commitment. Unlike the gas-powered Tradesman you might use for light runs, this engine is an industrial-grade tool designed to pull 20,000 lbs. But with great power comes a strict maintenance regimen.
In Kingfisher, we see too many "city trucks" fail prematurely because owners treat them like cars. The high-pressure common-rail fuel system and the complex exhaust aftertreatment system demand clean fluids and precise intervals.
If you are trading up from a 2022 model, note that while the core engine is similar, the sensor sensitivity and filtration requirements for 2026 are tighter than ever. This guide is your new bible for keeping that Cummins running for 500,000 miles.
The "Golden Rule" of Diesel Ownership
Before looking at the mileage table, understand this: Fuel quality is everything.
The #1 killer of the 6.7L Cummins is not mileage; it is water in the fuel. The high-pressure fuel pump (HPFP) is lubricated by diesel fuel. If water gets past your separator, it can scar the pump, sending metal shavings into your injectors (a repair bill that costs as much as a used sedan).
- Action: Drain your water separator monthly. It is located near the rear axle. If the "Water in Fuel" light comes on, stop driving immediately.
2026 Ram 2500 Cummins Service Intervals
| Mileage Interval | Service Required | Why It Matters for Kingfisher Owners |
|---|---|---|
| Every 7,500 Miles (or 6 mo.) | Oil & Filter Change | Severe Duty Standard. If you tow hay, cattle, or equipment, do NOT wait for 15k miles. Oil shears down under heat. |
| Every 15,000 Miles | Replace Fuel Filters (Front & Rear) | Critical. You have two filters: one on the engine and one near the tank. Replace BOTH to protect the HPFP. |
| Every 30,000 Miles | Transfer Case Fluid | 4WD launches in the mud break down this fluid. Keep it fresh to ensure 4-Low engages when you need it. |
| Every 50,000 Miles | Replace Crankcase Ventilation (CCV) Filter | A clogged CCV filter causes excessive crankcase pressure, leading to oil leaks and blown seals. |
| Every 75,000 Miles | Coolant Flush | Diesel engines run hot. Old coolant becomes acidic and eats away at the water pump and EGR cooler. |
| Every 100,000 Miles | Adjust Valve Lash | (If needed) Keeps the valvetrain quiet and maintains optimal compression for cold starts. |
Diesel Exhaust Fluid (DEF): What to Expect
The 2026 emissions system is aggressive to meet federal standards.
- Usage Rate: Expect to burn 1 gallon of DEF for every 50-75 gallons of diesel fuel.
- Towing Impact: When towing a heavy load (like a 30ft gooseneck), your DEF consumption will double. The engine runs hotter, creating more NOx, which requires more DEF to neutralize.
- Storage Warning: DEF has a shelf life. Do not buy bulk jugs and let them sit in your hot barn for a year. Old DEF crystallizes and will clog the injector nozzle. Buy it fresh from the dealership or a high-volume truck stop.
Automatic Transmission Service: 68RFE vs. Aisin
Your transmission dictates your service interval.
- Standard 68RFE (Standard Output Cummins): Service every 60,000 miles (Fluid & Filters). This transmission is great for daily driving but needs clean fluid to hold power.
- Aisin AS69RC (High Output Cummins): Service every 30,000 miles. The Aisin is a commercial-grade unit. It is stronger but requires more frequent attention to keep the clutch packs healthy.
Why Service Your Diesel at Johnsons of Kingfisher?
We don't just "change parts." We understand diesel diagnostics.
- Injector Balancing: We use factory WiTech tools to check the "return rates" of your injectors, spotting a failing unit before it melts a piston.
- Turbo Actuator Calibration: The variable geometry turbo (VGT) has moving vanes that can stick with soot. We perform cleaning cycles during major services to keep your boost instant.
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