Transfer case sealing KIT (ATC300)

The most common signs of failing ATC300 seals include visible oil spots on your driveway, a faint burning oil smell after driving, or noticeable wetness/grime around the ends of the transfer case shafts. If left unchecked, low fluid levels can lead to internal gear damage or total transfer case failure.

Yes, the ATC300 transfer case was primarily used in BMW E90, E91, E92 (3 Series) and E60, E61 (5 Series) xDrive models. If your vehicle uses the ATC300 unit, this kit is designed specifically to fit the shaft ends and prevent seepage.

While you can replace a single seal, mechanics usually recommend a full kit. If one seal has reached its end of life due to heat and mileage, the others are likely in similar condition. Replacing them all at once saves you on repeat labor costs in the future.

A sealing kit stops oil leaks. If the jerking is caused by low oil levels due to a leak, refilling the fluid and sealing the unit might help. However, if the shuddering is caused by worn internal clutches or a faulty actuator motor, you may need additional internal parts or a recalibration.

This kit is engineered to withstand the high thermal stresses and rotational speeds specific to BMW xDrive systems. Generic seals often use inferior rubber compounds that harden and leak prematurely under the high-pressure environment of a transfer case.