Signs of a Bad or Faulty Output Differential Seal

Common signs include whining sounds and differential oil leaks.

Differential output seals are seals located on the output shafts of a vehicle's differential. They usually seal the axle shafts from the differential and prevent fluid from leaking out of the differential during operation. Some differential output seals also help properly align the axle shafts with the differential. They are usually made of rubber and metal, and just like any other oil seal or gasket on a car, they can wear out and fail over time. Usually, a bad or faulty output differential seal causes several symptoms that can alert the driver to a problem that needs to be fixed.

Oil leaks from differential

The most common symptom of a differential output seal problem is an oil leak. If the seals dry out or wear out, fluid will leak out of the axle shafts through them. Small leaks can result in faint traces of gear oil leaking out of the differential case, while larger leaks will result in drips and puddles under the vehicle.

Howling or grinding from differential

Another sign of a potential problem with the output differential seal is a howling or grinding noise coming from the rear of the vehicle. If the output seals are leaking to the point where there is little fluid in the differential, this can cause the differential to make a howling, grinding or whining sound at the rear of the vehicle. The sound is caused by a lack of gear lubrication and may increase or change in tone depending on vehicle speed. Any noise in the rear should be fixed as soon as possible to reduce the potential for damage to any of the vehicle's components.

Differential seals are simple in design and function, but play an important role in keeping the differential and vehicle working properly. When they fail, they can cause problems and even serious damage to components due to lack of lubrication. If you suspect that your differential output seals may be leaking or have problems, have your vehicle checked by a professional technician, such as one from AvtoTachki. They will be able to determine if your vehicle needs a differential output seal replacement.