
CLUTCH
 AND
 TRANSMISSIONS
 7-20
COMPONENT PARTS REPLACEMENT
3.
4.
5.
6.
TRANSMISSION REPLACEMENT
 (EXC.
 CORVETTE)
Removal From Vehicle
1.
 Remove shift lever trim plate and dust boot.
Remove shift lever assembly.
Raise vehicle
 to
 desired working height.
Disconnect
 the
 speedometer cable from speedometer
driven gear fitting.
 .
 ~
 . •
Remove propeller shaft, then support engine
 at the
oil
 pan
 rail with
 a
 jack
 or
 other suitable support
capable
 of
 supporting
 the
 engine when transmission
is removed.
Disconnect shift lever bracket assembly from exten-
sion
 and
 remove
 all 3
 transmission shifter levers
from shifter shafts, (leave linkage connected
 to
levers)
 and
 remove bracket assembly levers
 and
linkage.
Remove extension mount7 to-crossmember attaching
bolts.
Loosen transmission crossmember
 and
 move rear-
ward
 or
 remove.
Remove
 the
 transmission-to-clutch housing retaining
bolts
 and
 install two guide pins, J-1126,
 in
 top holes.
Slide
 the
 transmission straight back until
 the
 input
shaft
 is
 free
 of
 splines
 in the
 clutch disc.
Slide
 the
 transmission rearward
 to
 allow sufficient
clearance
 of
 input shaft
 and
 clutch housing. Then tilt
input shaft
 end of
 transmission downward and with-
8.
9.
10.
11. 
draw transmission from vehicle.
installation
 to
 Vehicle
1.
 Raise transmission
 and
 rotate
 as
 necessary-to start
input shaft into clutch disc
 and
 slide transmission
forward until
 it
 bottoms against clutch housing.
 Re-
move guide pins.
2.
 Install
 the
 transmission-to-clutch housing retaining
bolts.
 Torque
 all
 four retaining bolts
 to 50 ft. lbs.
3.
 Raise engine
 and
 position extension mount
 to
 cross-
member,
 and
 loosely install
 the
 retaining bolts.
Tighten crossmember
 to
 frame retaining bolts.
4.
 Remove temporary support from engine, and torque
the extension mount retaining bolts.
5. Install propeller shaft.
6. Install control lever bracket assembly
 to
 transmis-
sion extension
 and
 connect shifter levers
 to
 shifter
shafts.
7. Fill transmission
 to
 level
 of
 filler plug hole with
correct lubricant specified
 in
 Section
 0.
8. Lower vehicle and install shift lever assembly, check
shift pattern and adjust linkage
 as
 required.
9. Install trim plate and dust boot.
CORVETTE TRANSMISSION REPLACEMENT
Refer
 to
 similar procedure under 3-Speed Corvette
Transmission.
FOUR-SPEED (SAGINAW) TRANSMISSION
INDEX
Page
General Description
 7-20
Maintenance
 and
 Adjustments
 . . 7-21
Shift Linkage Adjustment.
 . 7-21
Speedometer Driven Gear
 and
Oil Seal ................
 (See
 Muncie 4-Speed)
Side Cover
 7-22 
Page
Removal
 . . , 7-22
Disassembly
 . . 7-22
Assembly
 . . . 7-22
Installation
 . 7-22
Extension
 Oil
 Seal
 (See
 Muncie 4-Speed)
Transmission Replacement (See Muncie 4-Speed)
GENERAL DESCRIPTION
The Saginaw four speed fully synchronized
 (all
 forward
gears) transmission incorporates helical drive gears
throughout.
The main drive gear
 is
 supported
 by a
 ball bearing
 at
the front
 end of the
 transmission case and
 is
 piloted
 at its
front
 end in an oil
 impregnated bushing mounted
 in the
engine crankshaft.
 The
 front
 end of the
 mainshaft
 is
piloted
 in a row of
 roller bearings
 set
 into
 the
 hollow
 end
of
 the
 main drive gear
 and the
 rear end
 is
 carried
 by a
ball bearing mounted
 in the
 front
 of the
 extension housing.
The countergear
 is
 carried
 on a
 single
 row of
 rollers
at both ends while thrust
 is
 taken on thrust washers
 lo-
cated between
 the
 ends
 of the
 gear and
 the
 thrust bosses
in
 the
 case. Ah anti-rattle plate assembly
 at the
 front
 of
the countergear provides
 a
 constant spring tension
 be-
tween
 the
 counter
 and
 clutch gears
 to
 reduce torsional
vibrations.
 The
 sliding reverse idler gear
 is
 carried
 on
a bushing finish bored
 in
 place.
 It
 rotates
 on a
 short
idler shaft retained by
 a
 woodruff
 key.
The synchronizer assemblies consist
 of a
 clutch
 hub,
clutch sleeve,
 two
 clutch
 key
 springs and three energizer
clutch keys
 and are
 retained
 as an
 assembly on
 the
 main
shaft
 by a
 snap ring. 
A great deal
 of
 similarity
 and
 interchangeability
 now
exists between
 the new 3 and
 4-speed Saginaw trans-
missions.
However,
 the
 synchronizer assembly
 at the
 front
 of the
mainshaft
 is
 used
 for the
 third and fourth rather than
 the
second
 and
 third shift.
 The
 synchronizer assembly
 at
the rear
 of the
 mainshaft
 is
 used
 for the
 first and second
rather than
 the
 first
 and
 reverse shift. Gear teeth
 cut
in
 the
 first and second synchronizer sleeve (reverse gear)
distinguish
 it
 from
 the
 third
 and
 fourth synchronizer
sleeve.
Starting from
 the
 front, gears
 on the
 mainshaft
 are
third, second
 and
 first rather than second, first and
 re-
verse.
 A
 fourth blocker ring
 is
 used between
 the 1-2
synchronizer assembly
 and
 first gear
 on the
 four-speed
transmissions.
The cover
 on the new
 four-speed transmission
 is lo-*
cated
 on the
 left-hand side
 of the
 case.
 It is
 similar
 to
the three-speed cover with
 the
 addition
 of a
 reverse
shifter shaft assembly, detent ball
 and
 detent spring.
Disassembly
 and
 assembly procedures
 are
 covered
 in
this section.
CHEVROLET CHASSIS SERVICE MANUAL 

WHEELS AND TIRES 10-4
the road and it slips, grinding off the tread on the inside
half of the tire at an excessive rate. This type of tire
shows much the same appearance of tread wear as tire
wear caused by negative camber.
Second, the transfer of weight may also over-load the
outside tires so much that they are laterally distorted
resulting in excessive wear on the outside half of the
tire producing a type of wear like that caused by ex-
cessive positive camber.
Cornering wear can be most easily distinguished from
abnormal camber wear by the rounding of the outside
shoulder or edge of the tire and by the roughening of the
tread surface which denotes abrasion.
Cornering wear often produces a fin or raised portion
along the inside edge of each row in the tread pattern.
In some cases this fin is almost as pronounced as a
toe-in fin, and in others, it tapers into a row of tread
blocks to such an extent that the tire has a definite step
wear appearance.
The only remedy for cornering wear is proper in-
struction of owners.
Fig.
 5 - Tire Rotatidh
Rotation
To minimize the possibility of tire noise and to equal-
ize tire wear, it is recommended that tires be inter-
changed every 6000 miles as shown in Figure 5 or more
frequently in the case of extremely heavy wear.
NOTE:
 Rotate Corvette tires at 4000 miles or
sooner.
Interchanging tires will effectively prevent undue wear
on any particular tire. II tire interchanging is followed
as recommended above, all tires will have the same
number of miles in each wheel position at the end of the
fourth change. When interchanging tires, inspect for
signs of abnormal wear, bulging, etc., stones, glass, and
nails should be removed before reinstallation.
Noise
Noise caused by the normal action of tire treads on
various road surfaces is often confused with rear axle 
gears or other noises in the car.
The determination of whether tires are causing the
noise complained of is relatively simple. The car should
be driven at various speeds and note taken of part
throttle, and sudden acceleration and deceleration. Axle
and exhaust noises show definite variations under these
conditions, while tire noise will remain constant. Tire
noise is, however, most pronounced at speeds of approx-
imately twenty or thirty miles per hour.
The tires may be further checked by driving the ear
over smooth pavement with the tires at normal pressure
and again over the same stretch of pavement when the
tires have been inflated to fifty pounds pressure. Reduce
the tires to normal pressure one at a time to determine
the faulty tire or tires. This high inflation pressure
should immediately be reduced to normal after test. If
the noise for which the test is being made is caused by
tires,.
 it will noticeably decrease when the tire pressure
is increased, whereas axle noise should show no change
in volume.
If, on inspection, the tires on the front wheels are
found to be creating most of the noise the alignment of
the front wheels should be checked. Excessive tire noise
usually results from lower than recommended tire pres-
sure, incorrect alignment, uneven tire wear, or defective
(thumper) tire.
Cleaning
A great deal of ordinary road dirt which collects on
white sidewall tires may be sponged off with clear water
or a mild soap solution.
A good brand of whitewall tire cleaner, however, is
a quicker and more effective cleaner for removing dirt
and stains from whitewall tires and in many cases it
will remove stains and discoloration that the simpler
method of soap and water will not remove.
Under no circumstances should gasoline, kerosene or
any cleaning fluid containing a solvent derived from oil
be used to clean whitewall tires. Oil in any form is
detrimental to tire rubber and a cleaner with an oil base
will discolor or injure whitewall tires.
Change (W/Wheels)
To change the road wheels using the jack that comes
with the car, observe the following procedure:
1.
 Set hand brake and block front wheels if rear wheel
is being changed.
2.
 Remove hub cap or wheel disc and break wheel
mounting nuts loose.
3.
 Place the jack as directed tinder, General Informa-
tion,
 Section 0 and raise car until wheel clears
ground.
4.
 Remove wheel mounting nuts and remove wheel from
hub or drum.
5. To replace road wheel, reverse the above instrue-
. tions. Proper torque on nuts is 55-75 ft. lbs.
torque (70-85 ft. lbs. for Corvette aluminum wheel
nuts).
CAUTION: On models equipped with discs, in-
dex the pilot hole in the disc on the valve stem.
(To insure that the anti-rotation notches in wheel
disc register on lugs in wheel rim.)
CHEVROLET CHASSIS SERVICE MANUAL