Intermediate reduction drive (Description): Description and operation

Description

Intermediate Reduction Drive (IRD)

The IRD is fitted in place of the conventional transfer box and is attached to the manual or automatic gearbox. The combination of the two units provides drive to the front and rear wheels. The IRD incorporates a differential unit to control the proportion of drive delivered to each front wheel and, in addition, it operates in conjunction with the viscous coupling to give the vehicle a self-sensing four wheel drive system. The main casing, cover and pinion housing are manufactured from cast aluminium.

The unit comprises of a main casing, a RH housing, primary shaft, an intermediate shaft, a differential unit, a laygear, hypoid gear set, a rear output pinion and a pinion housing.

An oil cooler, connected to the vehicle cooling system, is fitted to prevent overheating of the IRD lubricating fluid. COOLING SYSTEM - Td4, DESCRIPTION AND OPERATION, Cooling System Component Layout – Manual Gearbox, Sheet 1 of 2. COOLING SYSTEM - K SERIES 1.8, DESCRIPTION AND OPERATION, Cooling System Component Layout. COOLING SYSTEM - K SERIES KV6, DESCRIPTION AND OPERATION, Cooling System Component Layout - Sheet 1 of 2 (All Except NAS and Gulf States).

The main casing also incorporates the oil level/drain plugs and a breather outlet. There are a total of seven taper roller bearings and one parallel roller bearing supporting the primary shaft, differential and output shaft assemblies.

Four seals, internal to the IRD, are used to prevent mixing of the IRD and gearbox lubricating fluids.