The front purpose of the differential is to manage the rotation of your vehicle's wheels. In front-wheel drive (FWD) vehicles, the transmission connects directly to the differential. In contrast, the differential in rear-wheel drive (RWD) sits between the two rear wheels of the vehicle. All-wheel drive (AWD) and similar vehicles will contain both a front differential and a rear differential. The differential is important in making turns and driving on uneven terrain. It allows your wheels to turn at different speeds to prevent skidding of the tires. It also works to prevent loss of traction in soft or uneven terrain (such as dirt roads).
The Importance of Differential Fluid
The differential fluid is usually referred to as differential oil or gear oil. The oil in your differential works to dissipate heat and lubricate the gears. Much like the engine oil, it will lose its ability to lubricate over time and requires regular service. Without healthy differential oil, the differential will rapidly overheat and wear down the gears.
Is it time to change?
If you've driven over 40,000 miles, it might be a good time to check the fluid. If you hear strange sounds from the differential, such as grinding or howling, it might be too late. At that point, the lack of lubrication has already damaged your gears. Another sign of bad differential oil is a burning smell. The oil will burn when it is no longer able to dissipate heat as it should. Check your vehicle's manual for a specific time interval. JAMHS Auto recommends a differential flush every 30,000 miles as part of your driveline service.