PFF19-2525R Lower Engine Mount Insert (Diesel) is made using our softer Red 65ShA material for a more subtle absorption of the NVH associated with standard diesel engines or those with automatic transmissions. Installing an insert into the upper portion of the voided cast rubber limits movement within the mount during acceleration and deceleration. By keeping the lower voided portion open, it limits the harmonic transfer of noise and vibration through the body of the vehicle, offering a perfect compromise between driving comfort and performance. The result is a restriction in engine movement, preventing wheel hop and offering more precise gear-shifting for a more positive driving experience. This, in turn, additionally prolongs the mount's life expectancy. NB: When strengthening the connection between the engine and chassis, a small increase in NVH, usually at idle, should be expected. Naturally, the harder the material used, the greater the NVH transmitted.