My 89 W250 360 TBI 727, NP205 137k drivetrain shakes at park. I can see the transfer case lever vibrate back and forth, maybe a 1/16 or 1/8 inch but enough to be visible. I can also feel the vibration in the steering wheel. I don't notice it when driving. The engine mounts and mounts under the transfer case only have a couple hundred miles on them, and all the engine accessories other then the water pump are new within the last several years. The harmonic balancer visually looks ok, but is there another way to check it? Is there another possible cause of the shake?