GMC 1982 Light Duty Truck, Руководство по обслуживанию

Страница: 1159 / 1435

MANUAL TRANSMISSION 7B-5
T R A N S M IS S IO N A L IG N M E N T
In some instances where excessive gear whine or high
speed gear hop out, particularly at 50 mph (80 k m /h ) and
up, are encountered, and after all other probable causes
have been checked, an alignment check of the transmission
and clutch housing may be helpful.
A special tool, on which a dial indicator is mounted, is
necessary to check the transm ission case rear bore
alignment. This tool may be made from a new or good used
clutch g e a r which has a good bearin g surface on the
crankshaft pilot end and at the front main bearing location.
The splines on the clutch gear shaft and the teeth on
the clutch gear should be ground off so the shaft may be
rotated in a clutch disc hub without interference when
assembled in the car. Weld a piece of 6.3mm (1 /4 in.) rod in
the mainshaft pilot bore long enough to extend out the case
rear bore. Assemble a good bearing on the clutch gear shaft
and secure it with the clutch gear bearing snap ring. A ttach
a suitable dial indicator to the rod.
1. Remove the transm ission from the vehicle and
completely disassemble, except for the reverse idler
gear. In any case where the clutch gear pilot or pilot
bearing is excessively loose or worn, the pilot bearing
should be replaced before checking the transmission
case rear bore alignment by the dial indicator method.
2. Carefully install the special tool with the dial indicator
in the transmission case with the face of the indicator to
the r e a r of the case an d with th e tracin g finger
contacting the I.D. of the case rear bore. Secure in
place with a clutch gear bearing retainer.
3. Assemble the transmission case to the clutch housing
and tig h ten the four transm ission m ounting bolts
securely. Be sure to clean off any paint or other foreign
material on the mating faces of the clutch housing and
transmission as any foreign material on these faces will
change alignment; also, check carefully for dings or
burrs on these mating surfaces and remove carefully as
necessary.
4. Dial indicate the transm ission case r e a r bore and
record the indicator readings in the 12, 3, 6 and 9
o’clock positions. It is best to start the reading at the 3,
6, 9 or 12 o ’clock position closest to the point where the
indicator plunger reaches its m axim um outward travel.
Se the dial indicator at " 0 " at this location and then
record the 3 , 6 , 9 and 12 o’clock readings in rotation.
5. Install te m p o ra ry slotted shims between the
transm ission case and the clutch housing in the
quantities and at the bolt locations as necessary to
bring misalignment at the transmission case rear bore
to a m axim um o f . 127mm (0.005 in.) indicator reading
in either th e vertical or horizontal direction.
E X A M P L E : If the m axim um indicator reading is at
the 12 o’clock position, put shims on the two bottom
bolts.
6. A fter the position and quantity of shims has been
determined and recorded, the transmission case may be
removed.
NOTICE: The clutch housing should then be stamped,
showing the position where shims are to be installed
and the thickness of shims at each location.
7. Inspect the external clutching teeth of the clutch gear
and second speed gear. Inspect the second and third
speed clutch internal clutching teeth. If the teeth are
worn or tapered, even slightly, the gears should be
replaced. Reassemble the transmission.
8. Install the transmission assembly to the clutch housing,
using the correct n u m b e r of shim s a t the proper
locations as previously determined. Shims are available
by unit part num ber with each unit consisting of the
following shims:
4—.002" shims identification—two corners cut off.
2--.005 " shims identification-one corner cut off.
1—.010" shims identification-all corners square.
These special shims have a tab on one end for ease of
installation. Do not slot the shims for the perm anent
installation.