Description (page 3 of 3)

FINAL DRIVE

DESCRIPTION AND OPERATION

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The differential comprises a pinion shaft and spiral bevel pinion gear and a crown wheel drive gear with an integral 
cage which houses two planet gears. Two sun wheels are also located in the cage and pass the rotational drive to the 
drive shafts.

The pinion shaft is mounted on two opposed taper roller bearings, with a collapsable spacer located between them. 
The spacer is used to hold the bearings in alignment and also collapses under the pressure applied to the pinion 
flanged nut. This allows the flanged nut to be tightened to a predetermined torque, which collapses the spacer, setting 
the correct bearing preload.

The pinion shaft has an externally splined outer end which accepts and locates the input flange, which is retained by 
the pinion nut. The output flange has six threaded holes and mates with the rear propeller shaft. Six bolts secure the 
rear propeller shaft to the input flange. An oil seal is pressed into the pinion housing and seals the input flange to the 
pinion housing. The pinion shaft has a spiral bevel gear at its inner end which mates with the crown wheel drive gear.

The crown wheel drive gear is located on the carrier and secured with ten screws. The carrier is mounted on taper 
roller bearings located in machined bores on each side of the pinion housing. The bearings are retained in the casing 
by a circlip, the thickness of which is selected to apply the correct bearing preload.

The carrier has a through hole which provides location for the shaft. The shaft provides the mounting for the planet 
gears in the carrier cage. The shaft is fitted with a snap ring at one end which locates in a machined groove in the 
carrier, locking the shaft in position.

The sun wheels are located in pockets in the carrier cage and mesh with the planet gears. Spacers are fitted between 
the sun wheels and the carrier and set the correct mesh contact between the planet gears and the sun wheels. Each 
sun wheel has a machined bore with internal splines and machined groove near the splined end. The groove provides 
positive location for a snap ring fitted to the end of each output flange.

Each output flange has a splined shaft which located in each sun wheel. A snap ring fitted to the splined shaft locates 
in the groove the sun wheel bore and positively located the output flange. Oil seals are pressed into each side of the 
pinion housing and seal the output flange to the housing. Each output flange has six threaded holes which provide for 
the attachment of the rear drive shafts.

The rear cover is located on the rear of the pinion housing and is sealed to the housing with a gasket and secured 
with eight bolts.