Transfer case shaft input (ATC450)

Common signs of a failing input shaft include a clunking noise when shifting gears, excessive vibration during acceleration, or a total loss of drive if the splines have stripped. If you notice metal shavings in your transfer case fluid, the shaft or its bearings may be deteriorating.

The ATC450 transfer case was primarily used in BMW X5 (E70 LCI) and X6 (E71) models produced roughly between 2010 and 2013. If your vehicle uses the ATC450 unit, this input shaft is the correct internal component for linking your transmission to the rear driveshaft.

Most failures are caused by spline wear. Over time, the constant torque and movement between the transmission output and the transfer case input can wear down the metal teeth (splines), eventually leading to a loss of physical connection and power delivery.

No, the transfer case must be removed from the vehicle and disassembled to replace the input shaft. This is a technical repair that involves opening the housing and ensuring all internal seals and bearings are properly seated upon reassembly.

The input shaft is the primary entry point for power. If it fails, the transfer case cannot distribute torque to the rear or front wheels correctly, which will typically trigger an 4×4/xDrive malfunction light on your dashboard and put the car into a limited drive mode.