1995 Nissan Pickup - Axle Bearing
What Causes Axle Shaft Bearing Noise?
An axle shaft bearing allows the axle shaft to rotate smoothly within the axle housing while supporting the weight of the axle shaft and keeping it centered. This is important to the smooth and safe operation of the vehicle, as the axle shaft bears the vehicle's weight and transmits power from the differential to the wheels. Adequate lubrication from axle bearing grease or gear oil is essential for maintaining axle bearings by reducing friction and dissipating the heat generated within the bearing during operation. Some axle shaft bearings are sealed and are unable to be greased, while others are serviceable and may be accessed through the wheel hub to add grease, or rely on the gear oil inside the differential and axle assembly to maintain lubrication. Over time, or due to poor lubrication or low gear oil levels, axle shaft bearings can wear out due to the constant load and rotation they endure. A lack of proper lubrication or damage to the axle shafts can also cause these symptoms to occur more rapidly due to increased friction. Common signs of a failing axle shaft bearing include noise, such as a rumbling or grinding sound from the wheel area, grease on the inside of the wheel, uneven tire wear, and handling issues. The bearing may also allow enough movement to "pop" when turning corners, and a damaged or stuck axle bearing can lead to wear on the axle shaft that may require repair or replacement. When a bearing begins to fail, it's essential to replace it promptly to prevent further damage and ensure safe operation of the vehicle. In some cases, this may also require the axle shaft seal to be removed and replaced as well to prevent continued leaks and ensure long bearing and axle shaft life. O'Reilly Auto Parts offers replacement axle bearings, seals, axle shafts, gear oil, and grease to help you perform a complete repair and keep your differential and axle assembly operating at its best. You can also learn more about how to change rear differential fluid with the resources in our How-To Hub.