Quick take: Keep a Jeep JK healthy with synthetic oil changes around every 5,000–7,500 miles, differential and transfer-case fluid every 30,000–60,000, and — if you wheel — extra fluid checks after water crossings plus regular steering/suspension inspections. Always follow the “severe duty” schedule if you go off-road.
Prefer a personalized schedule by mileage? Use the JK Service Interval & Maintenance Tool.
Routine Maintenance Intervals (Guide)
- Engine oil & filter: 3.6L synthetic ~5,000–7,500 mi (or per the oil-life monitor); 3.8L ~3,000–5,000 mi. Capacities: 3.6L / 3.8L.
- Tire rotation: every ~5,000–7,500 mi; re-torque lug nuts to spec — see lug nut torque.
- Differential fluid (front & rear): ~30,000–60,000 mi (sooner with off-road/water). Specs: Dana 30 front / Dana 44 rear.
- Transfer case fluid (ATF+4): ~30,000–60,000 mi — see transfer case specs.
- Automatic transmission fluid (ATF+4): ~60,000 mi under severe use.
- Spark plugs: inspect/replace around ~30,000 mi — gap/torque for the 3.6L here.
- Engine air filter: ~30,000 mi, sooner in dusty/off-road use.
- Brake fluid: every ~2–3 years.
- Coolant: long-life OAT — inspect condition and top up with the correct Mopar OAT coolant.
Off-Road / Severe-Duty Extras
- After any water crossing, check diff, transfer-case, and trans fluid for a milky look (water intrusion) and change if contaminated.
- Inspect ball joints, track bar, and tie rod regularly — loose steering parts are the root of death wobble.
- Re-torque suspension and lug nuts after trail abuse.
- Grease steering and driveline components on schedule.
- On the 3.6L, watch the oil filter/cooler housing for leaks — see the oil cooler upgrade.
Handy DIY Supplies
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- 5W-20 full synthetic oil and oil filter
- 75W-140 gear oil + friction modifier (Trac-Lok)
- ATF+4 for the transfer case/transmission
- A 1/2-inch torque wrench for lug nuts and drain plugs