Normal Vehicle Axle Maintenance

Rear axles and transfer case/Power Transfer Unit (PTU) containing synthetic lubricant and light duty trucks equipped with Ford-design axles are lubricated for life. These lubricants are not to be checked or changed unless service is required, or if a leak is suspected or the axle assembly has been submerged in water.

The axle and transfer case/PTU fluid should be changed anytime they have been submerged in water. Non-synthetic rear axle lubricants should be installed new every 4,800 km (3,000 mi) or 3 months, whichever occurs first, during extended trailer tow operation above 21°C (70°F) ambient and Wide Open Throttle (WOT) for extended periods above 72 km/h (45 mph).

The 4,800 km (3,000 mi) lube change interval may be waived if the axle was filled with 75W-140 synthetic gear lubricant. Add 118 ml (4 oz) of additive friction modifier for complete refill of Traction-Lok® rear axles.

The axle lubricant should be changed anytime an axle has been submerged in water.