JB Conversions 16-1206 User Manual

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HD Super Short SYE Kit

for the

NP231C or NP233C

Manufactured by JB CONVERSIONS, INC.

Phone: [phone]

Installation Instructions for the

NP231C or NP233C Transfer Case

Part No. 16-1206

Instruction Rev: 2009.10.28

Kit Components

1) Custom rear bearing housing (assembled)

2) 32 spline HD mainshaft

3) 1310 CV end yoke

4) Custom tone wheel

Applications: All applications of the NP231 or NP233 requiring a GM

speed sensor.

Note: Customer reuses existing GM speed sensor. If your sensor is

damaged or missing, a replacement sensor can be purchased as an

option.

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Installed photo.

Installation Instructions

Note: This kit can be installed without removing the transfer case

from the vehicle however it is recommended that the unit be removed

to ease installation of the SYE kit.

1) Drain the fluid from the transfer case. This kit can be installed while

the transfer case remains in the vehicle however, removal is

recommended for an easier installation.

2) Remove the 10mm bolts (4) holding the tail cone onto the bearing

housing (Fig.1).

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FIG: 1

3) Remove the retaining ring (Fig.2).

FIG: 2

4) Remove the 8mm bolts (5) holding the rear bearing housing onto

the rear case half.

5) Remove the bearing housing using a pry device. Be careful not to

damage the case during this process.

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6) Remove the retaining ring above the tone wheel (Fig.3).

FIG: 3

7) Remove the tone wheel (Fig.4).

FIG: 4

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8) Remove the lower retaining ring (Fig.5).

FIG: 5

9) Remove the 10mm bolts holding the two case halves together.

10) Gently pry the two halves apart using a screwdriver. There are two

locations in the case designed for use as pry points. Only use these

two locations. They are located on the sides of the case half.

11) Remove the spring from the top of the mode fork (Fig.6).

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FIG: 6

12) Lift the entire mainshaft assembly, chain, and front output shaft

out of the case as an assembly (Fig.7 & Fig.8).

FIG: 7

FIG: 8

13) Using flat-head snap ring pliers, remove the large retaining ring

which holds the hub to the mainshaft (Fig.9).

FIG: 9

14) Install the hub and sprocket assembly onto the new mainshaft

(Fig.10). If your sprocket has needle bearings located within the main

bore, press them out and discard. It is acceptable to delete these

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bearings. The deletion of these bearings is per factory, NVG design.

FIG: 10

15) Verify the length of your mode fork shift rod as shown (Fig.11). If

your shift rod measures 10.2", it will need to be cut down to a length

of 9.380". This is typical to 1988 and 1989 model YJ's.

FIG: 11

16) Be sure the large hub ring is arranged as shown in the photo. It is

possible to install this ring in a reverse orientation therefore causing

malfunction. Place the fork back into the hub groove being sure that

the pads are in place and of good condition (Fig.12).

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FIG: 12

17) Install the mainshaft assembly and mode fork into the case as

shown (Fig.13). The mode fork rod should be well lubricated before

performing this step. The lubricated rod should slide down through the

range fork easily. Install the spring you removed in step 11.

FIG: 13

18) Loop the chain around the main sprocket and front output shaft

then lower the front output shaft through the bearing until it seats

firmly (Fig.14).

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FIG: 14

19) Position the pump and pickup tube assembly into the rear case

half as shown (Fig.15).

FIG: 15

20) Install the rear case/pump onto the front case half as shown

(Fig.16a) and installl the 10mm bolts (Fig.16b).

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FIG: 16a

FIG: 16b

21) Place the tone wheel onto the mainshaft as shown (Fig.17). Do not

install the tone wheel in reverse. You will note that at this stage of

assembly, the tone wheel will rest on top of the oil pump. This is not

an issue. Installation of the yoke nut in Step 23 will draw the shaft

upward therefore raising the tone wheel off of the pump surface. You

will also observe that the tone wheel spins freely on the shaft,

however the tone wheel will become stationary upon tightening of the

nut in Step 23.

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FIG: 17

22) Install the new, rear bearing housing into position. Apply a thin

bead of silicone to the back of the housing mounting face and grease

to the seal lip before lowering the housing into place (Fig.18).

FIG: 18

23) Apply a small amount of RTV to the back side of the nut and in the

threads before tightening. Install the 5, 8mm bolts to hold the rear

housing in place. Install the yoke and nut as shown. Torque to 200 lb-

ft. (Fig.19). This kit does not utilize a rubber star washer beneath the

nut.

NOTE: If you experience an erratic speedometer needle, this is an

indication that the nut is insufficiently torqued. Retorque to

recommended amount.

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FIG: 19

24) Install the sensor into the rear housing and fill the case with
Chrysler ATF to complete the installation.