Power Transfer Unit (PTU)

The crown wheel drive gear is mounted longitudinally across the PTU. The gear is a low-offset hypoid bevel gear configured for minimal power loss across the speed range. The left end of the gear has splines which mate with corresponding splines in the transmission front differential output sleeve. The drive gear is hollow which allows for the fitment of the right halfshaft. The halfshaft is located through the hollow drive gear and mates with splines in the side gear of the transmission's front differential. The halfshaft is driven by the transmission front differential and receives no drive from the PTU.

The crown wheel is supported in the PTU casing on opposing angular contact ball bearings which are pressed into a housing and sealed with an O ring seal. The housing is fitted with a triple edge oil seal on the outer end of the housing which directs dirt and moisture away from the area of the drive gear. Another seal is fitted which prevents the ingress of dirt and moisture between the drive gear and right halfshaft.

The pinion gear is locked in the PTU casing at 90 degrees to the crown wheel drive gear. The pinion gear is supported in the casing on opposing taper roller bearings. The pinion gear is retained in the casing with a pre-load nut. The outer end of the pinion gear is splined and mates with the driveshaft output flange. The flange is secured with a nut which is screwed onto the pinion gear.

A collapsible spacer is located between the outer taper roller bearing and a shoulder on the pinion gear. The spacer collapses under pressure applied by the pinion nut and preloads the pinion bearings to the correct setting when the nut is torque tightened to a predetermined value.