Hi, Brick experts,

I just had the motor and transmission mounts replaced on my 945T which has over 220k miles. However, I did not notice a substantial reduction in the low pitch noise, much to my disappointment to a certain degree. The level of noise rises with engine speed. This noise I had believed is due to engine vibration. One hint was when putting into neutral at highway speed it is gone instantly. If I rev the engine in neutral the noise comes back up, perhaps not as loudly. Also in certain RPM range (3000 - 3400 roughly) the stereo face bezel and the cubby hole below it make buzzing sound and the buzzing goes away with the same testing maneuver as above.

I'd like to get the noise level down to as close to factory fresh condition as possible. Can someone recommend the possible / logical next steps? How valid will it be to rev the engine with the drive belts on (or off) one at a time? (load condition is different, isn't it?)

Additional information: I replaced these isolators primarily because I was not aware that it had been done before. The old parts do look quite worn and tired. Together with those mounts all accessory mount bushings and drive belts were replaced as well. I also had new control arm stay bushings, tie rod assemblies, control arm links, and sway bar bushings put in all at the same time.

Much thanks!

Lih-Yen