the car vibrates from 2200-2400 rpm in 4th gear. the tranny shop that did the install has no idea of what this could be. is they're anybody that can help me?

PI3200 installed for a few months.

john

 

Did the tranny shop pull the driveshaft or take out the torque arm during the shift kit install?

If so, check the pinion angle first. Make sure it's between 0 and -2 degrees (nose down). If the driveshaft was taken out, try rotating it 180 degrees in the yoke. If neither was done, then let's take this to the top for some other opinions.

 

Could it be the Tq converter clutch shuddering when going into lockup? Hmm...

 

The pinion angle is the angle of the nose of the rear axle in relation to the slope of the driveshaft (driveshaft angle). If the driveshaft is sloping downward (from the motor) at a 4 degree angle and the rear pinion is sloping up toward the driveshaft and motor at a 2 degree angle...this would make you pinion angle 2 degrees nose down (in relation to the driveshaft). Ideally, you want the pinion at the same angle as the driveshaft under Wide Open Throttle (WOT). To do that often means placing the nose of the rear axle 1-2 degreess nose down. Under WOT, the flexing of the drivetrain will bring the nose parallel to the driveshaft. If your pinion angle is more than +/- 4 degrees (nose up or nose down), you can experience vibration and wear out your u-joints pretty fast. This vibration will increase with speed. Check it to be sure.

 

thanks for the replies. i'm not sure if they pulled the drive shaft. my knowlegde of the TA driveshaft is pretty limited. so please speak newbie about this pinion angle. and i will certainly get it check out.
john