General Description

General Description

The LT230SE transfer box was introduced with 1999 Discovery Series II, and is currently the only North American Land Rover product with this gearbox. Mechanically it is essentially the same unit as others in the LT230 family, but with the addition of new sensors and switches. In Discovery Series II, the mechanical differential locking mechanisms are not used but remain present, their functionality replaced by the Electronic Traction Control (ETC) system.

The LT230SE transfer box is a constant mesh gear type unit, and transmits drive via high or low reduction ratios to the front and rear axles via the propeller shafts. The high/low ratios are 1.211:1 and 3.32:1 respectively.

North American specification transfer boxes have the prefix 42D to the unit serial number, indicating that the unit is equipped with a neutral interlock.

While similar to LT230Q transfer boxes fitted to other models, the LT230SE transfer box has certain engineering modifications incorporated which are as follows:
- Uprated torque capacity
- Modified front and rear output and cross shaft housings
- Intermediate gear bearing pre-load now controlled by a selective, non-collapsible spacer
- Speedometer drive and driven gears not fitted for this application
- Modified high/low hub
- Modified front output flange and mud shield
- Differential lock fitted but no longer driver operated
- Modified, cable operated, high/low selector lever and brackets
- Fixed setting of differential lock warning lamp switch

The speedometer drive has been deleted from the transfer box, with the vehicle speed signal now being supplied by the self levelling anti lock brake system (SLABS) Electronic Control Unit (ECU). The speedometer drive casing is therefore blanked off. High-Low shift is now cable operated. The ABS simulates the center differential lock, so no driver operation is available or required.