Basic Design
Input shaft, output shaft and reverse gear shaft
1. Pinion, 1st gear
2. Pinion, 2nd gear
3. Pinion, 3rd gear
4. Synchromesh hub 3rd - 4th gear
5. Synchromesh sleeve 3rd - 4th gear
6. Pinion, 4th
7. Pinion, 5th
8. Hub, 5th
9. Synchromesh sleeve, 5th
10. Gear, 1st
11. Synchromesh hub 1st - 2nd gear
12. Synchromesh sleeve 1st - 2nd gear
13. Gear, 2nd
14. Gear, 3rd
15. Gear, 4th
16. Gear, 5th
17. Gear, reverse
18. Synchromesh sleeve, reverse
19. Reverse pinion
The manual gearbox is a 5 speed box. All gears have synchromesh. The gearbox has relatively small rotating masses and thus low moment of inertia to be retarded at each gearchange. this makes gear changing easy and smooth and interior ware on balk rings and sleeves is almost non-existant. The balk rings are located on the input and output shafts.
Note that the gear wheels on the input shaft are called pinions (are driving), while the gear wheels on the output shaft are called gear wheels (are driven). The pinions on the 3rd, 4th and 5th gears are mounted in needle bearings to achieve the lowest possible losses from friction and thus a high degree of efficiency.
For better synchromesh function the 1st and 2nd gears have 3 balk rings. The 3rd, 4th and 5th gears have 3 leaf springs mounted between each balk ring and its hub. this is to ensure that the balk rings cannot move and generate noise when not under a load.
Input and output shafts have been mounted with taper roller bearings to achieve maximum rigidity in the shafts under load. the output shaft's roller bearing has been placed inside the final gear drive, which gives the shaft maximum insensitivity to high loads.
the workings of the gearbox are shown in the diagram. Power transmission from the engine is via the clutch, directly to the input shaft.
Power transmission 1st gear: When the car is driven in 1st gear, power is transmitted via the 1st pinion on the input shaft to the output shaft when the 1st gear wheel is secured to the output shaft on which it is mounted by the 1st/2nd synchromesh sleeve.
Power transmission 2nd gear: In a similar way to 1st gear, but instead the 1st/2nd synchromesh sleeve secures the 2nd gear wheel to the output shaft.
Power transmission 3rd gear: When driving in 3rd gear, power is transmitted via the 3rd pinion on the input shaft to the output shaft when the 3rd pinion is secured to the input shaft on which it is mounted by the 3rd/4th synchromesh sleeve.
Power transmission 4th gear: In a similar way to 3rd gear, but instead the 3rd/4th synchromesh sleeve secures the 4th pinion to the input shaft.
Power transmission 5th gear: In a similar way to 4th gear, but instead the 5th synchromesh sleeve secures the 5th pinion to the input shaft.
Power transmission, reverse gear: The reverse gear has an extra shaft (the reverse gear shaft). This shaft holds a journalled reverse gear wheel which is constantly meshed with the 1st gear pinion on the input shaft and a journalled reverse gear pinion which is constantly meshed with the 1st/2nd synchromesh sleeve on the output shaft. When driving in reverse gear, the power is transmitted from the 1st pinion on the input shaft to the reverse gear wheel by the synchromesh sleeve in this position meshing the reverse gear pinion with the reverse gear wheel. The power is then transmitted from the reverse gear pinion to the 1st/2nd synchromesh sleeve which drives the output shaft. Since the power from the input shaft to the output shaft goes via a third shaft, the desired direction of rotation is achieved for the reverse gear.