Chevrolet 30 Series 1967 Service Manual page 199

the nut gets to either end of the screw, the screw should
continue to turn, but the nut should not jam or run off the
ends.
Electric Motor. The closed type reversible field motor
(serviced only as an assembly) requires no lubrication
and cannot be disassembled for repair. Motor service­
ability can be determined by performing the following
tests.
With the motor housing connected to one battery term i­
nal, and either one of the two motor wires connected to
the other battery terminal, the motor will run in one di­
rection. With the other motor wire connected to the bat­
tery, motor will run in the opposite direction.
Connected to a 12 volt test circuit, the shift motor, free
running (no load), should "turn up" 10,000 RPM with a
maximum draw of amperes.
6
CAUTION: Do_ not overheat the motor while
making the following tests:
Place motor in vise, then clamp a small crescent
wrench on the rectangular drive on the armature shaft
and grasp wrench handle with one hand. Connect one
motor wire to a battery terminal and connect motor hous­
ing to the other battery terminal. The wrench should tend
to turn with a torque of about
turn very slowly, making sure that this pull or torque is
present the full 360 degrees turn of the wrench. If one
section of the armature is defective, the torque will dis­
appear for a small part of the 360 degrees.
Apply enough load to the motor in test circuit to mo­
mentarily stop armature rotation (stall the motor). The
current draw at stall should be a minimum of 40
amperes.
Miscellaneous P arts. Inspect bearing (10), if balls are
rough or chipped, replace with new bearing and snap ring
assembly. Pack bearing assembly with chassis lubricant.
Check torsion spring (17) for breaks or wear at lever
contact points.
F ig . 82 - Removing D rive Screw Bearing
in. lbs. Allow wrench to
6
REAR SUSPENSION AND DRIVE LINE 4-41
Observe condition of fiber contact bumper (24); if
broken or excessively worn, pull out old bumper and
press in new.
NOTE: All gaskets removed should be re ­
placed by new gaskets to assure proper sealing
of the unit.
Assembly
1. Install automatic switch assembly into housing using
flat head screw to attach switch to housing. On out­
side of housing, install insulator, and jam nuts on
switch terminal screws. Tighten nuts firmly.
2. Position motor cover gasket on housing and insert
motor (with cover) into housing. Install cable clip
and the three cover screws and lock washers.
Tighten screws firmly.
3. Attach motor wires to switch terminals. The longer
wire attaches to bottom terminal. Tighten terminal
nuts.
4. With a screwdriver inserted into slot of drive screw,
install bearing on end of screw with shielded side of
bearing toward inside as shown in Figure 82. Retain
bearing with bearing lock nut.
5. Run drive nut to center of drive screw, then insert
slotted end of screw into housing, meshing slotted
end with armature shaft.
MOTE:
Fiber bumper contact on drive nut
must be toward switch.
. Install bearing gasket and cover with three screws
6
and lock washers. Tighten screws securely.
7. Dip above assembly in S.A.E. 10 engine oil. With
drive nut on drive screw assembly in center of
screw, and fiber contact bumper down toward switch,
position the slots of winding lever over the drive nut.
Install the lever shaft through center of assembly
into depression in housing.
. Install front cover gasket on housing. Install housing
8
front cover with detent spring against drive nut. At­
tach cover securely with screws and lock washers.
F ig . 83 - Removir^ Motor W iring Lock Nuts
CHEVROLET TRUCK SERVICE MANUAL