When replacing the drive pinion gear, what else should always be replaced?

When replacing the drive pinion gear, it is essential to also replace the side gears to ensure the proper functioning and longevity of the drivetrain system. The drive pinion gear works in conjunction with the side gears in the differential assembly, contributing to the transfer of torque and power from the driveshaft to the wheels.

Replacing the side gears helps maintain the correct gear mesh and alignment, which is critical for preventing premature wear or failure. Over time, side gears can develop wear patterns that may not match the new pinion gear, leading to vibrations, noise, or even potential damage to the components. This alignment is crucial for the performance of the differential, ensuring that the torque is evenly distributed to the axles.

While other components like side bearings may also require inspection and potentially replacement during a pinion gear change, the focus on side gears stems from their direct interrelation with the drive pinion gear’s operation. Ensuring these parts are both new or adequately matched promotes optimal performance and reliability in the vehicle's functionality.