1. Manual Transmissions

2. Sliding Gear Transmission
Old school, used from late 1800’s to 1940’s?
Has two or more shafts in parallel with sliding spur gears.

3. Sliding Gear Transmission
If either gear is rotating, shifting is difficult and gear “clashing” will result.
Some manufacturers may still have a sliding gear for reverse.

4. Collar-shift Transmission
Has two parallel shafts with gears in constant mesh
These “collars” slide on a hub that is splined to the output shaft, thus transferring power.
Gear “clashing” will occur if the gear speeds are not matched by double clutching.

5. Double Clutching
The shifter, rather than going straight to the next gear, makes a stop in neutral and then the clutch is released.
This is to allow the engine to slow down (or with a tap on the gas, speed up when downshifting) so the transition into the next gear is much more smooth.
The driver then depresses the clutch again and completes the shift into the target gear, and finally the clutch is released again, putting the car back into gear.

6. Synchromesh Transmissions

7. Synchromesh Transmissions
Gears are in constant mesh and are collar shifted
All forward gears are of a helical design

8. Synchromesh Transmissions
Collars are equipped with synchronizers
Synchronizers eliminate the need to equalize gear speeds before engagement
Used on all current models of cars – may use a spur gear for reverse

9. Synchromesh Transmissions
Engine torque is applied to the input shaft (clutch shaft) when the clutch is engaged.
The input shaft is fitted with a gear (input gear or clutch gear)
The output shaft (main shaft) is inserted into, but rotates independently of the input shaft.

10. Synchromesh Transmissions
The different speed gears (1st, 2nd, 3rd 4th, etc.) rotate on the main shaft.

11. Synchromesh Transmissions
Parallel to (below or beside) the input and output main shaft is the counter shaft
The counter shaft is fitted with different sized gears.

12. Synchromesh Transmissions
All of these gears are in constant mesh with the gears on the output shaft except …
One gear is in constant mesh with the input shaft gear.

13. Synchromesh Transmissions
Gear changes occur when the selected gear is connected to the output shaft.
This is accomplished by locking a collar onto the selected gear.
The collars are moved by shift forks.

14. Synchromesh Transmission
Switch to ppt #2

15. Transmission Components
Input Shaft

16. Main (Output) Shaft

17. Counter Shaft

18. Synchronizer Assembly

19. Synchronizer Operation

20. Synchronizer Operation
First, the sleeve is moved toward the gear by the shift lever and engages the hub assembly
Second, the movement of the sleeve causes the inserts to press the blocking ring onto the cone of the gear

21. Synchronizer Operation
Third, when the components reach the same speed, the synchronizer sleeve slides over external dog teeth on the blocking ring and over the dog teeth of the speed gear’s shoulder. This action locks the gear to the main shaft.

22. Fork and Rail Assembly

23. Reverse Idler Gear

24. Transmission Operation
Power flow in neutral
The input shaft drives the counter shaft
All of the gears on main shaft rotate
The synchronizers are not engaged with any gear
No power is transferred to the output shaft

25. Power flow in first gear
The power enters the transmission through the input shaft
The first/second synchronizer sleeve is engaged with the first gear dog teeth
The power is transferred from the input shaft, through the countershaft, and up to the first gear
The first gear drives the output shaft

26. Power flow in second gear
The power enters the transmission through the input shaft
The first/second synchronizer sleeve is engaged with the second gear dog teeth
The power is transferred from the input shaft, through the countershaft, and up to the second gear
The second gear drives the output shaft

27. Power flow in third gear
The power enters the transmission through the input shaft
The third/fourth synchronizer sleeve is engaged with the third gear dog teeth
The power is transferred from the input shaft, through the countershaft, and up to the third gear
The third gear drives the output shaft

28. Power flow in fourth gear
The power enters the transmission through the input shaft
The third/fourth synchronizer sleeve is engaged with the fourth gear dog teeth
The power is transferred from the input shaft to the fourth gear
The fourth gear drives the output shaft

29. Power flow in fifth gear
The power enters the transmission through the input shaft
The fifth gear synchronizer sleeve is engaged with the fifth gear dog teeth
The power is transferred from the input shaft, through the countershaft, and up to the fifth gear
The fifth gear drives the output shaft in overdrive

30. Power flow in reverse gear
Reverse is often achieved by adding a third gear
-causing the output shaft to spin in the opposite (same) direction

31. Power flow in reverse gear
The power enters the transmission through the input shaft
The reverse gear synchronizer sleeve is engaged with the reverse gear dog teeth
The power is transferred from the input shaft, through the countershaft, through the reverse idler gear, and up to the reverse gear
The reverse gear drives the output shaft in reverse

32. GEAR RATIO FINAL
1st : :1
2nd : :1
3rd : :1
4th : :1
5th : :1

33. Transaxle
A manual trans-axle is almost identical to a manual transmission except:
1. The differential is built into the housing
2. The input shaft incorporates gears
2. The counter-shaft is now the output shaft
3. The gears are generally smaller and pressed fit to facilitate a smaller area.

34. Transaxle

35. Input and output shafts
Transaxle
Input and output shafts

36. Transaxle
First Gear

37. Transaxle
Fourth Gear

38. Transaxle
Reverse

39. Transaxle Final Drive

40. Shifter Rails

41. Interlock System

42. Fork and Rail Assembly (internal)

43. Fluids
… are used to
_ ?
…check the manufacturers specifications!