Transfer box - LT230SE (Description): Description and operation

Description

General

The LT 230SE transfer box is mounted at the rear of the gearbox 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.

Transfer boxes fitted to this model have the prefixes 41D and 42D to the unit serial number. Prefix 41D denotes that the unit is not fitted with interlock whilst 42D denotes that interlock is fitted.

Vehicles up to 03 model year – Whilst similar to LT230Q transfer boxes fitted to other models, the LT230SE transfer box has certain engineering modifications incorporated which are as follows: l Uprated torque capacity l Modified front and rear output and cross shaft housings l Intermediate gear bearing pre-load now controlled by a selective, non-collapsible spacer l Speedometer drive and driven gears not fitted for this application l Modified high/low sleeve l Modified front output flange and mud shield l Differential lock fitted to certain vehicles, but no longer driver operated l Fixed setting of differential lock warning lamp switch on vehicles fitted with differential lock

Vehicles from 03 model year – The LT230SE transfer box is as described above for vehicles up to 03 model year with the following modifications:

The following items are introduced on vehicles from 03 model year l Ribs added to main casing to reduce operating noise l Bearing retaining nut on the differential carrier has patchlock added to the threads l Interlock solenoid moved from main casing to selector lever assembly l Intermediate gears modified with machined internal shoulder and bearing circlips deleted

The following items are introduced later in the 03 model year build programme and therefore may not appear on all 03 model year vehicles l Driver operated differential lock (if fitted) l High/Low selector shaft fitted with spring assist l Existing differential lock switch replaced by new design switch. l New secondary differential lock switch installed in the front output housing

Construction

The transfer box comprises three main assemblies; the main casing, the front output housing and the rear output housing. Both output housings and all cover plates are sealed to the main casing by sealant; mud and water ingress being prevented by mud shields located on the output flanges.

Main casing

The main casing carries the mainshaft input gear, the intermediate gears and the differential, together with the high/ low range gears, selector shaft and fork. The front and rear output housings are bolted to either side of the main casing.

Transmission neutral sensor A transmission neutral sensor is fitted on automatic gearbox vehicles for North America and Japan. The sensor is connected to the BCU and is normally in the open position. The sensor provides an earth path for the BCU which then interprets the signal and activates an audible warning generated by the IDM if neutral is selected on the transfer box when the ignition is on.