Description

Description

Introduction
The LT230T transfer box is mounted at the rear of the main gearbox and transmits drive to the front and rear axles via the propeller shafts.

Construction
The transfer box comprises three main assemblies, the main casing, front output housing and rear output housing.

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 output housing carries the front output shaft and flange, high/low cross shaft, housing and selector and the differential lock selector shaft and fork. A dog clutch on the front output shaft is operated by the differential lock selector fork to engage/disengage the differential lock.

The rear output housing carries the rear output shaft and flange and the speedometer drive and driven gears. A mechanically operated transmission brake is attached to the housing, the brake drum being attached to the output flange.

All housings and cover plates are sealed to the the main casing by gaskets or sealant; mud and water ingress being prevented by mud shields and throwers located at each end of the output housings and on the drive flanges.

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. An additional power take-off gear is located at the rear of the input gear for certain applications.

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

Intermediate gear bearing pre-load is achieved by means of a collapsible spacer positioned between the bearings, the amount of compression applied to the spacer is by means of a nut on the end of the intermediate shaft.

Differential assembly
The differential assembly is supported at the front and rear by taper roller bearings, the bearing outer tracks being located in the front and rear output housings. 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 nut.

The differential assembly comprises front and rear half carriers with integral shafts and 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 the engagement of the sun gears and load 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.

For certain markets, a neutral warning lamp switch operated by the high/low selector shaft and an interlock solenoid are fitted in the main casing.

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

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.

The differential lock selector housing is also 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. A spring loaded detent ball fitted in the output housing locates in grooves in the shaft.

A differential lock warning lamp switch, operated by movement of the selector fork and shaft is screwed into the top of the output housing.

Range Rover Classic only - For certain markets, a neutral warning lamp switch operated by the high/low cross shaft is screwed into the side of the housing.

Rear output housing assembly
The rear output shaft is supported in the rear output housing by a single bearing and is splined into the differential rear shaft. The output shaft also carries the speedometer drive gear which meshes with the driven gear located in the rear output housing.

Lubrication
Lubrication is by splash, oil filler/level and drain plugs being located in the main casing. An oil temperature switch is also fitted for certain applications.