GM OEM Allison Transmission Mount 4wd. GM Genuine Parts Transmission Mounts are designed, engineered, and tested to rigorous standards, and are backed by General Motors. These mounts absorb drivetrain vibrations and are tuned to your vehicle, helping create a comfortable ride inside your vehicle's cabin. Additionally, these mounts are designed to function with surrounding components, helping eliminate possible interference with other nearby mechanisms. GM Genuine Parts are the true OE parts installed during the production of or validated by General Motors for GM vehicles.