What is the Transfer Case and How Does it Work?

The transfer case is a gearbox that splits the power between the front and rear axles on 4-wheel drive vehicles. In all-wheel-drive vehicles, the transfer case helps to shift power from one axle to another, depending upon traction conditions. Lubricating fluid in the transfer case, called gear oil, helps keep the gears cool, clean, and turning smoothly. Gear oil additives break down in all gearboxes at different intervals. Replacing this fluid at owner’s manual recommended intervals can help prevent premature wear and damage caused by contaminated or broken-down gear oil.

What is the Differential and How Does it Work?

The differential is part of your vehicle’s drivetrain. It is a special gearbox located between the drive wheels of your vehicle. Most 4-wheel drive vehicles have both a front and rear differential. The differential works with your transmission to deliver power from the engine to the axle that turns your wheels. The differential also makes turning your car possible. Using a series of gears, the differential allows the wheels to turn at different speeds. The differential gears are lubricated with a fluid that carries heat away from them, preserving their life and performance. Over time, high operating temperatures can cause the differential fluid to break down. If leaks develop, or if the differential fluid becomes contaminated or broken down, the gears may start to grind. If this happens, continued driving can cause expensive damage. Changing the differential fluid according to your owner’s manual will help you avoid premature wear on the differential. A general rule is to change the fluid between 45,000 to 60,000 kilometers.