Possible causes of engine vibration with automatic transmission:
Transmission problems:
* Worn or damaged friction discs
* Torque converter problems
*Low or contaminated transmission fluid
*Differential fault
* Cardan shaft failure
Engine problems:
* Uneven ignition
*Misfire
* Worn spark plugs or ignition coils
* Fuel injector malfunction
* Problems with the gas distribution mechanism (GRM)
Problems with engine and transmission mounts:
* Worn or damaged engine mounts
* Worn or damaged transmission mounts
* Uneven supports creating a load on one of them
Other possible reasons:
* Wheel imbalance
*Worn or damaged tires
*Steering fault
* Incorrect ignition or fuel injection adjustment
* Exhaust problems
* Incorrect engine or transmission installation
Diagnostics:
To accurately diagnose the cause of vibration, professional testing and inspection is necessary. The mechanic can use:
* Diagnostic scanner to check for fault codes
* Test drive with monitoring of engine speed and vehicle speed
*Physical inspection of transmission, engine and mounts
* Wheel balancing and tire wear analysis