Pontiac FIREBIRD 1972 Service Manual page 844

THREE SPEED MUNCIE TRANSMISSION
7B-5
Fig. 78-1 Cross Section of Transmission
1. Clutch Gear (Main Drive Gear)
2. Bearing Retainer
3. 3rd Speed Blocker Ring
4. 2nd & 3rd Speed Synchronizer
Assembly
5. 2nd Speed Blocker Ring
6. 2nd Speed Gear
7. 1st Speed Gear
8. 1st Speed Blocker Ring
9. 1st & Reverse Synchronizer
Assembly
10. Reverse Gear
1 1. Vent
SECOND GEAR
12. Speedometer Drive Gear and
Clip
13. Rear Oil Seal
14. Extension Housing
15. Rear Bearing-to-Shaft Snap
Ring
16. Rear Bearing-to-Housing Snap
Ring
17. Countershaft Woodruff Key
18. Thrust Washer
19. Reverse ldler Shaft Woodruff
20. Reverse ldler Gear
21. Reverse ldler Shaft
22. Countershaft Bearing Rollers
23. Countergear
24. Case Magnet
25. Anti-Lash Plate
26. Thrust Washer
27. Clutch Gear (Main Drive Gear)
Bearing
28. Bearing-to-Gear Snap Ring
29. Retainer Lip Seal
With the engine running and clutch engaged, the main
drive gear turns the countergear. The countergear, in turn,
rotates the 2nd, 1st and reverse idler gears. The reverse
idler gear turns the reverse gear.
In second speed, the 1st & Rev. synchronizer assembly
assumes a neutral position and the 2nd & 3rd synchro-
nizer sleeve is moved rearward on its hub to engage the
rotating 2nd speed gear. Since the 2nd & 3rd synchronizer
sleeve is keyed to its hub, and the hub is splined to the
mainshaft, torque is imparted from the rotating 2nd speed
gear through the synchronizer sleeve to its hub and hence
to the mainshaft, causing it to rotate in second gear.
THIRD GEAR
With the engine running and clutch engaged, the main
drive gear turns the countergear. The countergear, in turn,
rotates the 2nd, 1st and reverse idler gears. The reverse
idler gear turns the reverse gear.
In third speed (or direct drive), the 2nd & 3rd synchro-
nizer sleeve is moved forward on its hub to engage the
rotating main drive gear and the 1st & Rev. synchronizer
assembly remains in a neutral position. Since the 2nd &
3rd synchronizer sleeve is keyed to its hub, and the hub
is splined to 'the mainshaft, torque from the rotating main
drive gear is imparted directly through the 2nd & 3rd
synchronizer sleeve to its hub and hence to the mainshaft,
causing the mainshaft to rotate at the same speed as the
'
main drive gear. Thus, the vehicle is in direct drive.
REVERSE
With the engine running and clutch engaged, the main
drive gear turns the countergear. The countergear, in turn,