Signs of a faulty Mercedes automatic transmission torque converter:
Slipping
*Transmission slippage during acceleration
* Slow gear shifting
*Loss of engine power
* Failure of the torque converter lockup
Vibration
* Vibration when shifting gears or accelerating
* Vibration at idle
Noise
* Hum or howl when accelerating
* Noise when shifting gears
* Grinding sound
Other signs
*Transmission overheating
* Burnt oil smell
* Difficulty shifting gears
* Slowly moving the car from a place
Possible causes of torque converter malfunction:
* Worn lock-up clutch
* Freewheel malfunction
* Damage to pump or turbine blades
*Lack of transmission fluid
*Transmission filter clogged