Differential Fluid Service
One of the most over-looked maintenance issues.
Because of its location at the back under side of the vehicle, the differential rarely gets the attention the engine up front gets However, if the lubrication in the differential fails, you won't be getting very far for very long. Fortunately, you only need to change this oil every 65,000 - 110,000 kilometers depending on your car or truck.
Most people don't even know what a differential is. It's a component in all cars that compensates for the minute difference in distance the inner wheels and outer wheels travel as the vehicle goes around a corner.
Rear-wheel drive cars have the differential in its own housing and use a thick, dark oil 80 weight or heavier. (front-drive vehicles usually integrate the differential in the transmission housing and share the same fluid).
Changing your differential oil is just as important as changing your engine's oil because metal-to-metal contact wears down surfaces and creates heat from friction. This friction will weaken the gears and lead to failure.
This small procedure can save you a big headache and lots of money further down the road.