GMC 4000 Series Service Manual page 147

Sec. 4A
Page 140
REAR AXLE A N D CONTROLS
Figure 2 3 — Two-Speed Axle Vacuum Shift Cham ber
Installed (Corporation Axle)
INSTALLATION
1. At cable button clamping bracket, loosen
cable jacket clamp nut allowing cable to turn freely.
2. Insert cable into hole at top of valve cover
and insert cable into hole in cable trunnion. Install
and tighten cable securely, using trunnion screw.
3. Mount valve in the original location using
mounting screw s. Tighten cover tube nut.
Figure 2 4 — Sectional View of Two-Speed Axle Vacuum Shift Cham ber (Corporation Axle)
G M C S E R V I C E M A N U A L
ometer shifter changer, and shift chamber lines
to valve in their original location.
operating button bracket to shift lever so that
clearance exists between bottom of button and
bracket.
REMOVAL (Fig. 23)
hose from cylinder. Tag each hose so that it will
be replaced in proper position.
taching cylinder to differential carrier, then re­
move cylinder and housing assembly.
DISASSEMBLY (Fig. 24)
cylinder to each other, then separate two halves.
nut, then separate push rod from diaphragm.
then remove snap ring from inside of piston rod.
Pull push rod and spring assembly from piston rod.
seal can be driven from housing at this time.
4. Attach intake manifold, air cleaner, speed­
5. With cable button pushed down, position
SHIFT CHAMBER (CORP. AXLE)
1. Remove hose clamps, then remove vacuum
2. Remove three bolts and lock washers at­
1. Remove screws attaching two halves of
2. Using two wrenches, remove outer push rod
3. Push piston rod in to relieve spring load,
4. Should inspection indicate necessity, oil