This type of vibration causes the shift lever to oscillate, usually at relatively high engine rpm. It tends to be more selective about the rpm at which it vibrates. Of the various types of shift lever vibration, if the vibration occurs when the engine is idling, see the section on “Vibration at Idle”.
1.Main causes
Out-of-tune engine.
Imbalance in engine rotating or reciprocating components.
Resonance in the shift lever, or lack of rigidity of the shift lever.
Play between the shift lever and linkage, or worn bushings.
2.Mechanics of vibration development
(1)Front-engine. Rear-wheel drive vehicles
Engine torque fluctuations or imbalances in rotating or reciprocating components generate bending vibrations in the drive train. Moreover, the joint angles or an unbalanced propeller shaft may further amplify the vibrations.
The transmission extension housing is thus vibrated vigorously, generating a vibratory force which is transmitted to the shift lever.
The shift lever oscillates, since it is mounted on the transmission extension housing. Any play in the shift lever further amplifies the vibration.
(2)Front-engine. Front-wheel drive vehicles
An out-of-tune engine runs rough, causes the shift lever assembly to vibrate.