"O" - Off-Road Operation

When operating in off-road conditions:

- Change engine oil and install a new oil filter every 8,000 km (5,000 mi) or 6 months.
- Inspect and rotate tires every 8,000 km (5,000 mi).
- Change rear axle lubricant every 80,000 km (50,000 mi) (E-450 and F-450/550 only).
- Change transfer case fluid every 96,000 km (60,000 mi).
- Install a new cabin air filter as required (if equipped).
Inspect and lubricate U-joints and halfshafts.
- Inspect and lubricate steering linkage ball joints with zerk fittings.