INTRODUCTION - 6 SPEED GEARBOX

1.4 16v

CONSTRUCTION SPECIFICATIONS

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;

- a rear cover which contains the 5th and 6th speed gears and the rear bearing retaining plate for the main and layshafts;

- a casing joining the gearbox to the engine which contains the clutch, the thrust bearing and the control linkage.

1. Thrust bearing

2. Main shaft

3. Satellite gears

4. Planet gears

5. Toothed ring gear

6. 1st speed driven gear

7. 2nd speed driven gear

8. Gearbox casing

9. 3rd speed driven gear

10. 4th speed driven gear

11. Rear bearing retaining plate

12 - 5th speed driven gear

13. 6th speed driven gear

14. Layshaft

15. Rear cover

16. 6th speed drive gear

17. Gearbox bell housing

Main shaft

The main shaft consists of:

- 1st and 2nd speed and reverse gears formed 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 layshaft 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.

Synchronisers

The synchronisers for the forward speeds are the Borg-Warner type.

The synchroniser arrangement is known as the split type because the synchronisers 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 parked in neutral because 3 of the 6 pairs of gears are not driven.

The engagement and synchronisation loads are also reduced as a result of the corresponding reduction in the inert rotating masses downstream of the crankshaft.

Differential

The differential unit is located in the rear part of the gearbox casing.

It comprises:

- a reduction cylinder pair

- a differential housing in a single piece, incorporating the planet and satellite gears.

The differential is supported by two taper roller bearings.

The planet gears have a splined internal profile in which the two joints connected to the two axle shafts that transmit the drive to the wheels mesh.