3239209 - Introduction - MANUAL GEARBOX AND DIFFERENTIAL
DESCRIPTION
Gearbox structure
The structure of the gearbox consists of:
- gearbox casing which contains and supports the main and layshafts, rods and gear selector forks and the gear selector and engagement device.
- a rear cover which contains the 5th speed gears, the 5th speed engagement fork and the rear bearing retaining plate for the main and layshafts
- the bell housing which contains the clutch and the coaxial clutch control
1, Main shaft
2, 5
th
speed drive gear
3, 4
th
speed drive gear
4, 3
rd
speed drive gear
5, 2
nd
speed drive gear
6, 1
st
speed drive gear
7, Reverse speed drive gear
8, Layshaft
9, Planet gears
10, Planet gears
11, Ring gear
12, Mileometer reverse idler gear
13, Gear casing
14, Clutch casing
15, Differential mount casing
16, Gear casing cover
17, Clutch coaxial control device
Main shaft
The main shaft consists of:
- 1st , Reverse and 2nd speed gears
- 3rd , 4th , 5th speed gears, fitted on needle bearings with the synchronizers
3 rd , 4 th and 5 th speed gears fitted on the shaft make it possible to:
- reduce shift loads during synchronisation
- reduce gearbox noise while in neutral.
Layshaft
The layshaft consists of:
- 1st and 2nd speed gears, fitted on needle bearings with synchronizers
- 3rd , 4th and 5th speed gears fitted on the shaft.
The layshaft is supported on:
- a roller bearing at the pinion end
- a ball bearing at the cover end.
Gears
The gears are the following type:
- helical toothed for the forward speeds
- straight toothed for Reverse.
Synchronizers
The synchronizers for all the gears are brass, baulk ring, single-cone "Borg-Warner" typeGear shift/selection system
The gear shift/selection system consists of:
- a swinging control (1) connected to selector dog (2)
- selector dog (2) which operates sliding rods (4) fitted with synchronisation sleeve control forks (3, 5, 6, 7).
1, Fluctuating control
2, Selector dog
3, 1
st
and 2
nd engagement/selector fork
4, Sliding rods
5, 5
th engagement/selector fork
6, 3
rd
and 4
th engagement/selector fork
7, Reverse engagement/selector fork
Safety devices
The safety devices consist of:
- three dowels (1) that prevent two speeds being engaged at the same time
- dowel (3), pin (4) and spring (5), which maintain reversing dog (2) in a safe position to prevent dangerous movements of revesing fork (9) with the attendant possibility of engaging reverse.
- Lever (10) and spring (11), which prevent involuntary engagement of revese while changing from 5th to 4th speed.
1, Safety dowels
2, Reverse dog
3, Dowel
4, Pin
5, Spring
6, 5
th
and Reverse rod
7, 3
rd
and 4
th rod
8, 1
st
and 2
nd rod
9, Reverse selector fork
10, Lever
11, Spring
Differential
The differential consists of:
- a crown wheel and pinion reduction
- a differential housing constructed in a single piece which includes the differential and planet gears.