One of the symptoms most commonly associated with bad or failing differential or gear oil is a noisy transmission or differential. If the gear oil runs low or becomes excessively dirty, it can cause the gears to whine or howl as they turn.
What can a bad differential cause?
This is why it is important to pay attention to signs of differential trouble, including the following.
Can a rear differential mess up transmission?
When the differential doesn't perform well, it creates metal-on-metal friction that wears down surfaces. The resulting heat weakens gears and can cause component failure and transmission problems.
How do I know if my limited slip differential is bad?
Related Question Can a bad differential cause transmission problems?
How do you know if you have a locking differential?
If you jack up just one rear wheel and it spins freely, then it's an open differential. If you jack up just one rear wheel and it does not spin freely, then it is some sort of locking or limited slip differential.
How much does it cost to change the differential fluid?
You'll only pay somewhere between $80 and $140 for differential fluid change. The labor should be between $50 and $70, while parts can cost anywhere from $30 to $70.