Gearbox Mount Insert This part fits as an insert for the Gearbox Mount. The rubber on the original mounts degrades and soften with time resulting in excessive engine and gearbox movement. This insert is developed to fit in and around the voided sections of the original rubber mounts to restrict movement at higher torque levels. This provides a cost-effective way of improving engine stability, gear shifting, power delivery, and vehicle handling without the increased NVH associated with more expensive full replacement aftermarket engine mounts.