Driveline vibration

[Luistt]

anyone else have a problem after lowering there Silverado. After I did a 2x4 drop when I hit 80 mph the driveline starts to vibrate. Anyone find a fix for this. 

[D_Mackler]

That's very common with any lifting or lowering. You're changing the pinion angle on the rear axle which can cause vibrations. You have to shim the axle to get the angle where the truck is happy (stops vibrating). Different trucks take different shims to alleviate the issue, you may only need 1-2 degrees worth of shims.