Chevrolet 10 Series 1967, Service Manual

Page: 399 / 605

CLUTCHES AND TRANSMISSIONS 7-13
THREE-SPEED TRANSMISSION (MUNCIE)
IN D EX
Page
General Description......................................................... 7-13
Maintenance and Adjustments.......................................... 7-13
Transmission Linkage A d ju s t m e n t........................... 7-13
Speedometer Driven G e a r .......................................... 7-13
Mainshaft Oil S e a l .......................................... .. 7-13
Page
Transmission Side Cover .......................................... 7-14
Service Operations............................................................ 7-15
Removal from V e h i c l e ................................................ 7-15
Installation in Vehicle................................................... 7-15
GENERAL DESCRIPTION
Two three-speed synchromesh transmissions are used
as standard equipment on 10-20 Series (1/2 and 3/4
ton) trucks. The Muncie transmission incorporates all
helical gears which are machined from drop forged steel
gear blanks, heat treated and shot peened for strength and
long life. The shafts are machined from high grade steel,
heat treated and ground to close limits.
The rear end of the clutch gear is supported by a heavy
duty ball bearing at the front end of the transmission case
and is piloted at its front end in an oil impregnated bush­
ing mounted in the engine crankshaft. The front end of
the mainshaft is piloted in a double row of roller bearings
set into the hollow end of the clutch gear and the rear end
is carried by a ball bearing.
The countergear is carried on roller bearings at both
ends while thrust is taken on thrust washers located be­
tween ends of gear and front and rear of the case.
The reverse idler gear is carried on ball-indented
bronze bushings while thrust is taken on thrust washers
located between ends of gear and front and rear of the
case.
The Sagninaw three speed fully synchonized transmis­
sion is the same as used in passenger vehicles. Refer to
the Passenger Chassis Service Manual for service
procedures.
Gearshifting is manual through steering column gear­
shift mechanism to the transmission cover located on the
side of the transmission. Shifting is accomplished by
two rotating cranks which directly engage the gears to be
shifted, thus affording a highly efficient mechanical ac-
Fig. 1G - Steering Column G earshift
tion. The shifter gate for selection between first and
reverse and second and high is contained in the shifter
housing mounted on the lower portion of the steering col­
umn mast jacket. Two shifter control rods connect the
shifter levers on the transmission to the outer shifter
levers on this housing.
MAINTENANCE AND ADJUSTMENTS
TRANSMISSION LINKAGE ADJUSTMENT (Fig. 1G)
In cases where gearshift linkage has been disconnected
justment to the steering mainshaft should be
checked as outlined in the procedure in Section
9 of this manual.
or
1
.
2
.
3.
4.
removed, proper adjustment sequence is important.
Install control rods to both second and third shifter
lever and first and reverse shifter lever. Set both
shifter levers in neutral position.
Align both shifter tube levers on mast jacket in the
neutral position. Position relay lever so that gear­
shift control lever is in neutral position.
Connect control rods to tube levers making sure
clamps are properly adjusted so that tube levers and
transmission shifter levers remain in their neutral
positions while tightening. On Chevy Van Models, a
small pin or nail may be used in the holes of the
shift flange and shifter levers to obtain neutral align­
ment of the shift levers.-
Move selector lever through all positions to check
adjustment and insure over-travel in all positions.
NOTE: If mast jacket lower dash clamp has
been disturbed at its mounting on dash, its ad-
SPEEDOMETER DRIVEN GEAR
Disconnect speedometer cable, remove lock plate to
housing bolt and lock washer and remove lock plate. In­
sert screwdriver in lock plate slot in fitting and pry fit­
ting, gear and shaft from housing. Pry "O" ring from
groove in fitting.
Install new "O” ring in groove in fitting, coat "O" ring
and driven gear shaft with transmission lubricant and in­
sert shaft.
Hold the assembly so slot in fitting is toward lock plate
boss on housing and install in housing. Push fitting into
housing until lock plate can be inserted in groove and
attached to housing.
MAINSHAFT OIL SEAL
Replacement
1. Remove nuts and U-bolts retaining rear universal
CHEVROLET TRUCK SERVICE M ANUAL