Transmission Mount Bushing Failure

Bushings Split in the front...

And the back!

While coasting down the road the shift knob would move significantly combined with a low frequency 'THUMP' when the gas is re-applied. The factory Motor mounts were replaced with VF Engineering's billet versions thinking this issue would be solved. Apparently, the ultimate root cause was failed pendulum mount bushings. The pendulum mount was already replaced with VF Engineering's highly acclaimed billet version.
VF Engineering

New vs. Old

After raising the car and supporting the engine, the mount was easily removed. The split bushings can be seen on the right. Both sets of top and bottom bushings (4 total) were split vertically from top to bottom of the bushing.

Everything Nice and Clean

Ready to install!

Ready to drive!

A thorough cleaning of all the billet parts was required. Much road grime had accumulated and the bushing seats need to be clean to seat well. Of course, the rest of the car is not very clean. Reassembly was simple and torque was specified in the installation instructions from VF. All that remained was to lower the vehicle and test drive.