Freelander System Description and Operation
INTERMEDIATE REDUCTION DRIVE
41-4
DESCRIPTION AND OPERATION
Oil Seals
1 Primary shaft outer oil seal
2 Primary shaft inner oil seals
3 RH drive shaft oil seal
4 Pinion housing oil seal
5 'O' ring seal
Externally, three oil seals prevent lubricating oil escaping from the gearbox and the IRD unit. The gearbox gear case
houses the oil seal for the left-hand front driveshaft, and the RH housing on the IRD unit houses the oil seal for the
right-hand front driveshaft, with the remaining oil seal located in the pinion housing of the IRD.
There are also four internal oil seals in the IRD unit. Two smaller diameter oil seals are fitted internally at each end of
the primary shaft. These prevent oil ingress along the intermediate shaft from the IRD unit at the differential end. At
the opposite end, the seal prevents oil ingress from the gearbox along the intermediate shaft. Two larger oil seals are
fitted in the main casing where the IRD unit enters the gearbox. The inner oil seal prevents oil ingress from the IRD
primary shaft entering into the area between the two seals, and the outer oil seal prevents oil ingress from the gearbox
entering the same area.
On the underside of the main casing is a 'tell-tale' drilling which is positioned between the inner and outer primary
shaft oil seals. Oil leakage from the drilling will indicate either a faulty inner or outer primary shaft oil seal. An 'O' ring
seal, fitted in a machined groove, seals the IRD main casing to the gearbox housing.
