Rear axle and final drive (Rear differential): Description and operation

REAR DIFFERENTIAL

Description

The rear differential assembly serves to convert the "angle of drive" through 90° and distribute drive, in the desired proportions, to both rear wheels. The type of rear differential fitted is an integral carrier housing hypoid-gear in which the centre line of the drive pinion is mounted below the centre line of the ring gear. To minimise weight, the differential housing is manufactured in aluminium alloy, and the assembly is secured to the rear subframe by way of three rubber bushed mountings.

The differential housing incorporates the drive pinion gear shaft, which is supported by two opposed taper roller bearings fitted to the pinion and cups assembled into the carrier housing. The pinion bearing pre-load is controlled by a collapsible spacer and the torque of the pinion nut. The pinion position is controlled by a selective shim located between the inner pinion bearing cone and the pinion gear head.

The differential assembly is supported by two opposed taper roller bearings. The bearing cups are secured in the housing by removeable bearing caps. Shims are located between the differential bearing cones and differential case for controlling differential bearing pre-load and ring gear to pinion gear backlash.

The differential casing rear cover is manufactured from pressed steel and is sealed to the casing with RTV silicone sealant. The cover also incorporates the oil filler plug. A breather is located in the top of the differential casing to prevent pressurisation of the casing.

The pinion oil seal, which is fitted in the differential casing, is referred to as a "labyrinth" type seal and is especially designed to prevent contaminant ingress. The oil seal works in conjunction with a pressed steel shield, referred to as a "flinger" which is pressed on to the pinion drive flange. The two drive shafts are also sealed by "labyrinth" type oil seals fitted in the differential housing.

The differential oil level should be maintained to the bottom of the filler plug. No oil changes are specified.