TRANSFER BOX - LT230SE (Description): DESCRIPTION AND OPERATION (page 2 of 5)

TRANSFER BOX - LT230SE

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DESCRIPTION AND OPERATION

Mainshaft input gear
The gearbox output shaft is splined into the mainshaft input gear which is supported by taper roller bearings.

Input gear bearing pre-load is achieved by the use of a selective shim located in the bearing housing.

Intermediate gears
The intermediate gear cluster is supported by the taper roller bearings located at each end of the cluster and runs on 
the intermediate shaft which, in turn, is supported at the front and rear by the main casing.

A selective spacer, positioned between the gears, pre-loads the intermediate gear bearings when the intermediate 
shaft nut is tightened sufficiently to achieve the correct 'torque to turn' of the intermediate gears.

On vehicles from 03 model year, the circlips used to retain the bearings in the intermediate gear are deleted. The bore 
of the intermediate gear is machined with a shoulder at each end to locate the bearings.

Differential assembly
The differential assembly is supported at the front and rear by taper roller bearings, the front bearing outer track is 
located in the front output housing and the rear bearing outer track is located in the main casing by the rear output 
housing. Bearing pre-load is achieved by means of a selective shim located in the front output housing.

The differential rear shaft carries the low range gear, high/low selector sleeve and hub, high range gear and bush and 
the differential rear bearing; these components being secured to the shaft by a special staked nut.

The differential assembly comprises front and rear half carriers with integral shafts and with sun and planet gears 
mounted on cross shafts within the half carriers. Dished, non-selective thrust washers control the engagement of the 
planet gears with the sun gears, whilst selective thrust washers are used to control engagement of the sun gears and 
'torque to turn' of the differential. The differential carrier halves are bolted together, a retaining ring providing positive 
location of the cross shafts.

The high/low selector shaft and fork are located at the side of the differential, movement of the shaft, fork and selector 
sleeve being controlled by the high/low selector finger. A spring loaded detent ball fitted in the main casing, locates 
in grooves in the shaft.

On vehicles from 03 model year, the selector fork is modified and fitted with a spring assister and clips to reduce the 
effort required to move the selector lever.

Front output housing
The front output housing carries the front output shaft and flange, high/low cross shaft, housing and selector and on 
certain vehicles, the differential lock selector shaft and fork.

The front output shaft is supported in the housing by a single bearing and is splined into the differential front sun gear.

High/low selector
The high/low cross shaft is located in a housing bolted to the top of the output housing and is connected to the high/
low selector finger which locates in a slot in the selector shaft.

High/low detect switch
A high/low detect switch is fitted in the front output housing and connects to earth when low is selected. The switch is 
connected to the engine ECM, the SLABS ECU and the EAT ECU. The purpose of the switch is to enable selection 
of the hill descent feature and to modify the engine fuelling and automatic gearbox gearshift maps stored within the 
respective ECM's and ECU's.

Differential lock - If fitted
The differential lock selector housing is bolted to the top of the front output housing, the selector finger passes through 
the housing, locating in a slot in the differential lock selector shaft. The differential lock selector shaft passes through 
the selector fork which is located beneath a plate bolted to the side of the output housing. The selector fork engages 
the dog clutch sleeve with the differential rear shaft when the splines of the sleeve and differential rear shaft are 
aligned. A spring loaded detent ball fitted in the output housing locates in grooves in the shaft.