The structure of the gearbox consists of:- a gearbox casing containing and supporting the main and layshafts, the gear engagement forks and rods and the gear selector/engagement device.- rear cover which contains the 5th and 6th speed gears and the bering retaining plate for the main and layshafts;- a casing joining the gearbox to the engine which contains the clutch, the thrust bearing and the linkage.
The main shaft consists of:- 1st, 2nd speed and Reverse gears directly on the shaft;- 3rd, 4th, 5th and 6th speed gears fitted on the shaft.The main shaft is supported by a front roller bearing and a rear ball bearing.
Layshaft
The lay shaft consists of:- 1st, 2nd, 3rd, 4th, 5th and 6th speed gears fitted on the shaft.The layshaft is mounted on:- a front roller bearing- a rear ball bearing.
Gears
The gears are the following type:- helical toothed for the forward gears- straight toothed for Reverse gear.
Synchronizers
The synchronizers, for the forward speeds, are the Borg-Warner type.The synchronizer arrangement is known as the split type because the synchronizers for 1st and 2nd speeds are fitted on the layshaft, whilst those for 3rd, 4th, 5th and 6th speeds are on the main shaft.This solution reduces gearbox noise when stopped in neutral from the moment that 3 of the 6 pairs of gears are not driven.The engagement and synchronization loads are also reduced as a result of the corresponding reduction in the inert rotating masses downstream of the crankshaft.
Differential
The differential is located in the rear part of the gearbox casing.It comprises:- a crown wheel reduction- a differential housing in a single piece which incorporates the planet and satellite gears.The differential is supported by two conical roller bearings.The planet gears have a splined internal profile in which the two joints connected to the two driveshafts that transmit the drive to the wheels mesh.
