How to Install a Rubicon Express HD Slip Yoke Eliminator Kit For NP231 Transfer Case on Wrangler

Suspension systems or components that enhance the off-road performance of
your vehicle may cause it to handle differently, on and off-road, than it did from
the factory. Care must be taken to prevent loss of control or vehicle rollover
during sudden maneuvers. Failure to drive the vehicle safely may result in serious
injury or death to driver and passengers. We recommend you always wear your
seatbelt, drive safely and avoid quick turns and other sudden maneuvers.
Constant maintenance is required to keep your vehicle safe. Thoroughly inspect
your vehicle before and after every off-road use.

We recommend that certified technicians perform the installations of our
products. Attempts to install these products without knowledge or experience
may jeopardize the safety of the vehicle. These instructions only cover the
installation of our products and may not include factory procedures for
disassembly and reassembly of factory components. Read instructions from start
to finish and be sure all parts are present before disassembling the vehicle.
Included instructions are guidelines only for recommended procedures and in no
way are meant to be definitive. Installer is responsible to insure a safe and
controllable vehicle after performing modifications. Do not perform test drives on
public roads with partially completed installations. Always double and triple check
your work before use.

1 DS 2-70-18X U-joint strap kit
1 RM11510 4-Bolt SYE CV output flange
1 HWC10040 Bag kit #14 including;
1 21/64 Drill bit
1 3/8-24 Tap
1 3/8-24 X 1 HSC Bolt
1 3/8 Lock washer
1 5/16 Flat washer through hard
4 7/16-14 X 1-1/2 HSC Bolt
4 7/16-14 Nylock nut

Prior to installation, please read both installation options and decide which option is right for you. The output flange in this kit is designed for use with an RE1898 type CV drive shaft.

INSTALLATION OPTION 1 - Installation on vehicle w/o splitting transfer case.

1 Remove drive shaft.

2 Measure and mark shaft so that 1-1/8” to 1-1/4” of splined shaft will remain.

3 Cut output shaft with abrasive cutting wheel.

4 Grind end of shaft square, and chamfer and de-burr the splines.

5 Center punch shaft to ensure drill starts in center of shaft.

6 Using drill and 3/16” drill bit, start pilot hole in end of shaft.

7 It may be helpful to remove the stock slip yoke from the drive shaft and use it as a guide. To do this, first drill a 3 /16” pilot hole centered at the dimple in the end cap of the slip yoke. Install slip yoke onto shaft and drill a 3/16” hole, 1-1/4” deep into the shaft.

8 Next, bore out 3/16” hole with supplied 21/64” size drill bit. Remove stock slip yoke if used as a guide.

9 Use supplied tap to cut threads in output shaft. Use cutting oil while cutting threads and keep tap clean by backing it out often. Use caution to not force the tap.

10 Install output flange using supplied 3/8”-24 bolt and lock washer. Be sure to use thread lock.

11 Install RE1898 type flanged CV drive shaft using supplied 7/16” nuts and bolts at flange, and supplied u-joint strap kit at pinion yoke.

12 Grease u-joints and slip splines in drive shaft.

13 Check transfer case fluid level.

14 Test drive and inspect for leaks.

15 Re-tighten bolts and re-grease drive shaft after first 100 miles.

INSTALLATION OPTION 2 - Modifying shaft outside of transfer case.

1 Refer to factory manual for instructions on removing shaft from transfer case.

2 Cut shaft so that 1-1/8” to 1-1/4” of splined shaft will remain (use steps 3-4 of option 1 for reference).

3 Drill and tap the shaft to accept supplied 3/8”-24 bolt (use steps 5-9 of option 1 for reference).

4 Reinstall shaft in transfer case.

5 Follow instructions in option 1 starting with #10.