Rubicon Express RE6030 - Manual (Page 4)

RI 60106030 Page 4 of 4
LIFT KIT TROUBLESHOOTING
Rear driveline:
Acceleration vibration: Caused by the pinion being too high in relation to the transfer case output shaft. On leaf sprung vehicles, install axle shims to
lower pinion accordingly.
Deceleration vibration: Caused by the pinion being too low in relation to the transfer case output shaft. On leaf sprung vehicles, install axle shims to
raise pinion accordingly.
Slip yoke vibration: Caused by excessive angle on the transfer case slip yoke. Very common on vehicles with 2” or more of lift. Lifts of 2”-3.5” can
sometimes be cured with a transfer case drop kit (pinion adjustment may also be required- see acceleration and deceleration vibration troubleshooting
above). If this does not cure it, it will likely require installing a slip yoke eliminator (SYE) kit and CV drive shaft. Adjust pinion so it is 2 degrees below
parallel with CV drive shaft (see acceleration and deceleration vibration troubleshooting above). A transfer case drop kit can usually be omitted with a
CV drive shaft.
Drive shaft bind (84-95 XJ’s): A condition of interference between slip yoke and tube yoke. This is usually only a problem with over 3.5” lifts. A high
travel slip yoke (part #RE1822) may remedy this. Later XJ's already have the high travel slip yoke and may instead require an SYE and CV drive shaft
(see above slip yoke notes).
High speed wobble:
Fairly common with y-type steering on lifted XJ's. A condition where front tires will shimmy after hitting a bump. Avoid bias ply tires and wheels with
excessive offset. Check for worn or loose parts. In most cases a reduction of positive caster will eliminate this condition. A good rule of thumb is
minimum factory caster and maximum factory toe in. Note that lift heights increased with coil spacers (or taller coils) may exhibit wobble that cannot be
corrected with alignment.
Bump steer:
Caused by improper relationship of drag link and track bar. To correct, center axle again following the instructions supplied with the track bar. Next
determine the neutral position of the steering wheel. Adjust the drag link to center the steering wheel.