Chevrolet 30 Series 1967 Service Manual page 196

REAR SUSPENSION AND DRIVE LINE 4-38
SPEEDOMETER
ADAPTER
IGNITION
SWITCH
RED"-'
'
(TO T E M P . P IN K )
CIRCUIT BREAKER
B LA C K
1. M otor Attaching Screw
2. C ab le C lip
3. Motor Assembly
4 . M otor C over Gasket
5. Shift Housing
6. Bushing
7. Insulator
As the nut moves downward, the spring winding lever,
which pivots on a pin in the nut, winds the torsion spring.
Thus the tension of the spring is increased, and in this
position, the axle is ready to shift into the high speed
ratio as soon as the load on the axle gears is relieved.
The torsion spring is assembled in the unit so that it is
under 65 pounds pressure. When the spring is wound by
the winding lever, this tension is increased to 115 pounds.
This additional pressure is used to shift the axle. When
the shift is completed, the ends of the spring come to­
gether, leaving the original tension in the spring. This
preload tension holds the axle in either range.
A CCESSO R Y
T E R M IN A L
MANUAL
CONTROL
SWITCH
R IB B E D ,
V— □ ----
CONNECTOR
Fig . 7 4 - Electric Shift Control System W irin g Diagram and Shift Unit Details
9. Jam N ut
10. Bearing Assembly
11. Lock N ut
12. Bearing Cover
Gasket
13. Bearing C over
14. Screw
SHIFT MOTOR
AUTOMATIC
SWITCH
15. Actuating Lever Shaft
16. Actuating Lever
17. Torsion Spring
18. Spring W inding Lever
19. C over G asket
20. Front C over
21. F ille r Plug
LOW SPEED RANGE
When the control switch operating arm is moved to the
down (LO) position, current is supplied to the other field
of the motor and to the speedometer adapter. The cur­
rent now causes the armature and screw to turn counter­
clockwise, and the nut travels toward the top of the screw
(fig. 78). This winds the torsion spring for a shift to low
range which is accomplished in the same manner as the
shift to high range.
22. C o ver Screw
23. Drive Screw Assembly
24. Contact Bumper
25. Terminal N u t
26. Switch Screw
27. Sw itch Assembly
28. Sw itch G asket
CHEVROLET TRUCK SERVICE M ANUAL