Torque Converter Shake
 

Has anyone ever heard of and know about torque converter shake. My car has had the motor and transmission mounts changed, front flex disk changed and the center support bearing apparently looks good. However, I get an intermittent shake that occurs around 2000 rpm 40 mph and seemingly right before the 2 to 3 gear shift. It varies in intensity, usually worse when applying a little more throttle.

Does the transmission in a 96 C280 have lockup? I believe it's a 722.4?

since the TC is turning at engine speed any TC relayed vibration will be felt any time the engine is turning. Rev the engine in Park, Vibration = torque converter, flywheel or engine. No LU Clutch in a 722.4 transmission Maybe you have a 2/3 shift chatter, it the above test pass, adjust the modulator CW two turns.

My car 92 500sel also shakes at around 2000rpms in either drive or neutral. PO had tranny rebuilt and they didn't do it right. There is whining nouse from tranny on idle and that shake and vibration around 2000rpm. My tranny is similar to c280 tranny, should be same family. Please let me know if you find the cause of your shake and I will be unbolting the torquw converter from flywheel hopefully next week and will run the engine to see if vibration goes away. I will report back. Good luck

What is "shift chatter"?