The short answer
Ram's 2026 2500/3500 owner handbook says to change the oil when the oil change indicator calls for it, but never go past 8,000 miles, 12 months or 350 engine hours on the 6.4L HEMI, or 15,000 miles, 12 months or 500 hours on the 6.7L Cummins, whichever comes first.
That HEMI limit is shorter than the 10,000-mile limit in the 2026 Ram 1500 handbook. Diesel trucks also get both engine-mounted fuel filters every 15,000 miles, a crankcase ventilation (CCV) filter at 75,000 miles and power steering fluid at 97,500 miles.
The schedule, from the manual
| Item | 6.4L HEMI (gas) | 6.7L Cummins (diesel) |
|---|---|---|
| Oil and filter | Indicator; never over 8,000 mi / 12 months / 350 hours | Indicator; never over 15,000 mi / 12 months / 500 hours |
| Tire rotation | Every 10,000 mi (and at the first sign of irregular wear) | Every 7,500 mi |
| DEF | — | Check and refill every 7,500 mi |
| Cabin air filter | Every 12,000 mi | Every 12,000 mi |
| Engine air filter | Replace every 30,000 mi | Inspect every 15,000 mi; never beyond 15,000 mi or 24 months |
| Fuel filters | — | Replace both engine-mounted filters every 15,000 mi |
| Brakes and parking brake | Inspect every 20,000 mi | Inspect every 22,500 mi |
| Transfer case fluid | Inspect at 30,000 and 60,000 mi (change at 60,000 for frequent towing or fleet use); change at 120,000 mi | Inspect at 30,000 mi (change for frequent towing or fleet use); change at 60,000 mi |
| Automatic transmission fluid | — | Change every 60,000 mi (TorqueFlite automatic) |
| Spark plugs and PCV valve | Every 100,000 mi | — |
| Crankcase ventilation (CCV) filter | — | Every 75,000 mi |
| Power steering fluid | — | Flush and replace every 97,500 mi |
| Engine coolant | 10 years or 150,000 mi | 10 years or 150,000 mi |
HEMI vs. Cummins: what the schedule means for you
The diesel goes longer between oil changes but adds fuel filters, DEF and a CCV filter. The HEMI changes oil more often but has fewer diesel-only items. Either way, Ram says severe service (high ambient temperature, short trips, heavy loading, trailer towing, off-road) may shorten oil intervals. For the buying side of that choice, see is the Cummins worth it?
Owner checks once a month
Monthly or before a long trip (handbook)
7 itemsYour ticks are saved only in this browser. Print or screenshot the list to bring it along.
The diesel 'Perform Service' message
On the Cummins, the instrument cluster shows "Perform Service" when emissions maintenance is due, which may include replacing the CCV filter element. It's separate from the oil change indicator.
Booking it in Barron
Swant Graber Motors (Chevrolet, Ram, Dodge), 1690 E Division Ave, Barron, 715-537-5657. Service hours: Monday–Friday, 8:00 a.m.–5:00 p.m. (no Saturday service). Service loaners are available; ask the service department when you book. You don't have to use a dealer to keep your warranty; keep receipts wherever the work is done.
Questions
How often should I change the oil in a 2026 Ram 2500 HEMI?
When the oil change indicator says, and never more than 8,000 miles, 12 months or 350 engine hours, per Ram's handbook.
How often does a 2026 Cummins need an oil change?
When the indicator says, and never more than 15,000 miles, 12 months or 500 hours, per the 2026 Ram 2500/3500 handbook.
How often are Cummins fuel filters replaced?
Both engine-mounted fuel filters every 15,000 miles, per the handbook's diesel maintenance plan.
Why is the Ram HD HEMI oil limit shorter than the Ram 1500?
Ram's handbooks set different limits: 8,000 miles for the heavy-duty gas engines and 10,000 miles for the Ram 1500. Follow the handbook for your truck.
Next steps at Swant Graber
Swant Graber Motors (Chevrolet, Ram, Dodge): 1690 E Division Ave, Barron, WI 54812, 715-537-5657. Swant Graber Ford: 1697 E Division Ave, 715-537-9500. Search new or used inventory, or see shop near you for model-by-model answers.
