A differential is a set of gears that allows the driven wheels of a vehicle to rotate at different speeds when traveling around corners or over rough terrain. These gears necessitate lubrication, which is commonly referred to as differential fluid, gear oil, or gear lube. Despite the fact that modern vehicles have significantly more horsepower, torque, and towing capacity than their predecessors, the design of differential gears and bearings has remained largely unchanged.

When Should Differential Fluid Be Replaced?

The answer is determined by the manufacturer. For the proper service interval, always refer to your owner's manual. In most cases, differential fluid should be changed every 30,000 to 50,000 miles. Because metal-on-metal contact generates heat from friction, it's critical to stay on top of changing differential fluid. It also wears down surfaces and weakens gears. This can result in differential failure, which is a costly issue.

Differential fluid keeps the differential operating at peak performance for an extended period of time.  It is intended to perform under high-pressure conditions rather than at high temperatures, as engine oil is. It lubricates clutch packs, gears, and bearings; lubricates the ring and pinion gears that transfer power from the driveshaft to the wheel axles; and -cools and lubricates the differential.

The differential would overheat if there was no differential fluid because of metal-on-metal contact. That means it would burn out, potentially causing safety issues and necessitating costly repairs.

Differential fluids are classified into two types. Mineral oil, for example, is a natural, crude oil-based fluid. The other type of differential fluid is synthetic differential fluid, which is created in a laboratory. Synthetic differential fluid oils, like all synthetic oils, can be fine-tuned for optimal performance.

When differential fluid levels fall below a certain level, the gears begin to grind, which can lead to differential failure. Differentials do not have an oil filter, unlike motor oil, which does. Small metal shavings or pieces may appear when a differential experiences unwanted friction, causing significant damage to the differential.