To eliminate any driveline vibration you may experience after installing a lift kit on your Wrangler YJ, install the Zone Offroad 1-5/8" transfer case drop. This kit comes with new fasteners and a transfer case shifter relocation bracket to re-align the linkage with this drop. Installation will lower the transfer case to reduce the rear driveline angles. This is commonly used with the Zone Offroad rear pinion cam locks. The cam locks use the factory axle provisions to rotate the rear pinion to more closely match the drivetrain angle.
This transfer case lowering kit is typically used with a 4" lift kit when the stock slip yoke rear driveshaft is used.