How often should my 4WD be serviced?

Hi Paul, after reading your article about how the 4WD and differential systems work, I realised that my mechanic has serviced my Toyota Land Cruiser’s gearbox twice but has never serviced the differential. How often should the differential be serviced? Sam Onyait.

Hello Sam, differential gear oil for your Toyota should be renewed every 50,000 or 80,000 kilometers depending on your car manufacturer’s service schedule and the gear oil recommended drain interval.
Unfortunately, differential gear oil change is one of the most overlooked service routines until the differential gears fail. The differential ring and pinion gears work hard and tend to heat up as they transfer power from drive shafts to the rear or front wheel axles.

Differential systems also help to compensate for the difference in distance between inner and outer wheels as you drive around a corner. Good differential gear oil is designed to lubricate and prevent metal sheer or frictional damage, corrosion and overheating.
Overtime differential gear oil efficacy will reduce as the active protective and performance enhancing additives age. The oil will change to a darker colour and thicker viscosity and will cease to protect the differential or enhance its performance.
This is the time when the differential gear oil should be renewed to prevent expensive metal sheer damage or seizure of the gears. After 100,000 kilometres it helps to renew the gearbox transfer case oil as well.