PFF1-1130R  Lower Engine  Mount  Insert  is made in our softest  Red 65A  durometer material, specifically for Diesel models, helping to  limit NVH transmission. Designed to fill  the voiding in the OE rubber  mount, it smooths out gear changes by stiffening and supporting the often perished rubber bush, which is common for failure on tuned vehicles. This will provide a more precise and settled transmission  response during acceleration and  deceleration.  A small increase in NVH, usually at idle, should be expected when  stiffening the connecting mount  between the engine/transmission and chassis.  The harder the material used, the greater the NVH transmitted.