
Primary shaft is produced, as like whole with gear. Front support the shaft is situated on the flywheel and doesn`t perceived axle efforts. Rear support (in the gear case) fixes the shaft from axial displacement. The front support is established on radial bearings (a,b).
Table of Contents
Schemes of the front support the primary shaft of the gearbox

Sliding and needle bearings are used on the cars for front support (c). Front bearing is effectively ‘sealed for life’.
In this case, it is advisable to equip the bearing with protective washers or seals that retain lubrication and protect the clutch discs from oiling (c). Sometimes the grease is supplied to the front bearing through the grease nipple 1, which is screwed into the flywheel, through channels 2 in the flywheel (b).
The rear support of primary shaft have the radial bearings, which are fixed in the case of gearbox by the lock ring (a). When the gearbox is separate from engine the primary shaft is established on the two bearings situated in the side cap of gearbox case. See the picture 2.
Schemes of the rear support the primary shaft of the gearbox

Rear bearing of primary shaft has a protective washer (c,d). This washer save the bearing from the metal particles that can be appear from gear wear.
Scheme the primary shaft situated when the gearbox is separate from engine

The primary shaft and sheave used in passenger vehicles are precision machined parts with Din 9 accuracy that are milled and broached.