HI Julio,
Seems the vibration of the steering wheel is from the wheels which should need some balancing done.
As to the gear shifting, it should not be jerking when upshifting or downshifting.
Check if the trans throttle pressure cable is properly adjusted.
THROTTLE CONTROL CABLE
NOTE: Before adjusting throttle control cable, ensure throttle cable connecting accelerator pedal to throttle body linkage has .39-.47" (10-12 mm) deflection with throttle closed. If deflection is not as specified, loosen lock nuts and adjust throttle cable.
1. With engine idling at normal operating temperature (cooling fan comes on), loosen throttle control cable adjustment lock nuts at transaxle control lever bracket.
2. Adjust lock nuts to synchronize movement of transaxle throttle control lever and throttle body throttle lever/linkage. Tighten adjustment lock nuts.
Thursday, December 18th, 2008 AT 7:36 AM