PLEASE READ THESE INSTRUCTIONS BEFORE ATTEMPTING TO DISMANTLE THIS DIFFERENTIAL ASSEMBLY. FAILURE TO DO SO MAY RESULT IN DAMAGE TO THE UNIT.

This differential unit incorporates a twin cross-pin assembly and four planet gears. The kit is made to accept standard production crown wheels and standard differential output shafts of your choice, which can be Hardy Spicer type (Cooper S), Rubber Coupling or Pot Joint – but NOT the Pot Joint output shafts used in diffs that do not use the centre thrust block. Carefully inspect your output shaft gear teeth if fitting second hand output shaft. If any pitting is seen or excessive wear, they must be replaced. Fit new side gear thrust washers (part no. BTA101) to the differential output shafts. Before you can fit your output shafts, carefully dismantle the unit in the following sequence.

1. Remove cross-pin cap-head lock screw with the 3/16 AF hex key supplied.

IMPORTANT:- ONLY USE HAND PRESSURE FOR DISMANTLING AND ASSEMBLY OPERATIONS 2 TO 9.

2.Insert a tool with a small diameter shaft (a 3mm diameter punch or small cross-head screwdriver for example) into the hole created by removal of the cap-headed screw and use tool to lever this short pin out away from the main body. Once it is sticking out a little way it can be carefully fully removed with pliers. But DO NOT grip pin tightly with pliers – there should be no marks made in the pin surfaces. These pins are a light slide fit. Once removed, place on bench.
3. Push/pull out the long cross-pin that passes completely through the centre thrust block.
4. Remove the centre thrust block/cross-pin by pulling it inwards. WITH ALL PARTS NOW REMOVED THE UNIT IS READY TO BE ASSEMBLED
5 Fit your output shaft with new thrust washer into the housing.
6. Carefully note the angled cross bore in the central thrust block and its relationship with the transverse cross-pin hole in the housing. This bore only allows the thrust block to be fitted in one plane. Viewing the main housing from the Crown wheel mounting face and with the cap-head screw hole at the 12 o’clock position, the cross-pin bore in the thrust block should be below the horizontal centreline on the left hand side and above the centreline on the right hand side when viewed in this position. Fit planet gear and bronze thrust washer onto thrust block pin and refit to main body housing bore which is opposite to the cap-headed screw hole and mesh planet gear teeth with those on the output gear. Ensure locating tab on bronze thrust washer locates in cut-out in main housing.
7. Align the transverse hole in the thrust block to the housing cross-pin bore by dummy assembling the long cross-pin through the housing and thrust block. Now withdraw the long cross-pin and fit the planet gears and thrust washers into the housing. Again ensuring the locating tab on the bronze thrust washers locate in cut-outs in main housing. Refit the long cross-pin to pass through the planet gears, thrust washers and thrust block. Note: the larger countersunk hole at the centre of the long cross-pin locates the locking peg on the short cross-pin and should be correctly aligned at this stage of the assembly.
8. Start the short cross-pin into the main housing visually aligning the cross-pin retaining hole with the screw hole in the housing. Allow space to fit the thrust washer and planet gear. Finally locate the short cross-pin through the thrust washer, planet gear and into the thrust block. Slight sideways movement on the long cross-pin may be necessary to allow the locking peg on the short cross-pin to enter its countersunk locating register in the long cross-pin (see item 7 above). Refit the cap-head retaining screw in the housing to retain the short cross-pin.
9. Fit the remaining output gear shaft with new BTA101 thrust washer. Using new crown wheel bolts and lock tabs, refit the crown wheel (see data box below for torque setting).
10. Check for free running operation of the differential assembly, having torqued crown wheel bolts. Finally tab over lock washers.

Parts list for C-AJJ3385 –
Twin Cross-pin diff assembly:
1 x Differential Main Housing x1
4 x Thrust Washer Bronze – DAM5071 x 4
4 x Planet Gear 2 x Thrust Washer – BTA101
1 x Cap Screw - UNF special
1 x Twin Cross-pin Assembly
1 x Hex Key Please note the cross-pin spider assembly can be bought as a service kit.

Torque setting: Crown wheel bolts 60ft/lbs Cap screw Hand tight with hex key