* Low gear oil: Insufficient or low-quality gear oil will cause increased friction and lead to a whine. This is the most common and easiest to fix.
* Worn gear teeth: Over time, the gears inside the differential wear down, leading to noise. This is a more serious problem requiring repair or replacement of the affected gears.
* Worn bearings: The pinion bearings or differential bearings can wear out, causing a whine, especially under load or at certain speeds. This also requires repair or replacement.
* Damaged pinion gear: The pinion gear, which drives the ring gear, can be damaged, causing a whine.
* Loose or damaged differential components: While less common, internal components could be loose or damaged, creating the whine.
* Incorrect gear oil viscosity: Using the wrong weight gear oil can also contribute to noise.
It's crucial to diagnose the specific cause. The pitch and intensity of the whine, as well as whether it changes with speed or load, can help a mechanic pinpoint the issue. Ignoring the problem could lead to more significant damage and potentially catastrophic failure of the rear differential. Have a qualified mechanic inspect the rear differential as soon as possible.
