Differential & Transfer Case Servicing
Maintain your differential or transfer case in good working order
It’s not unusual for automatic transmission or gearbox specialists to also work on differentials, as the components perform a similar task:
- The transmission or gearbox adapts the engine output to suitable speed and torque to be transferred to the wheels.
- The differential channels that power to the two wheels on the same axle at an appropriate ratio. This is because when the vehicle turns, the outside wheel takes a slightly longer path than the inside one, so has to run that little faster.
The differential sits between the wheels, where the drive shaft connects with the axle. Depending on whether your vehicle is front-wheel drive, rear-wheel drive or four-wheel drive, the differential is on the front, rear or both axles.
In addition to differentials, four-wheel drive cars have a transfer case. The transfer case acts like a differential, but channels power to the two differentials on different axles rather than to two wheels on the same axle.
As in a gearbox, a differential and transfer case require fluid to lubricate the gears, shafts and bearings where metal slides over metal. The oil also transmits heat away from the working surfaces. However, as time goes by, the fluid tends to become dirty or can even be contaminated by water, losing its ability to do its job effectively.
A differential or transfer case seldom give cause for concern in most modern cars, as long as they’re serviced regularly. You should really have your differential and transfer case checked by professionals every 50,000km at least. Having these parts serviced requires only a small fraction of the cost of rebuilding or replacing a differential.
A differential or transfer case seldom give cause for concern in most modern cars, as long as they’re serviced regularly. Servicing requires only a small fraction of the cost of rebuilding or replacing a differential.
What the service includes:
- Drain differential gear oil
- Inspect the oil for evidence of sludge
- Fill the differential with new oil of the correct type
- Reseal differential cover if needed
- Check for leaks and wear on seals
- Test to check working of serviced differential.
While a differential or transfer case is a relatively straightforward mechanical device, it’s worth making sure that nothing goes wrong with them.