
SECTION 6K
ENGINE COOLING
INDEX
Page
General Description . . . 6K-1
Maintenance and Adjustments 6K-1
Coolant Level 6K-1
Coolant System Checks 6K-1
Periodic Maintenance 6K-2
Cleaning 6K-2
Reverse Flushing 6K-2
Radiator 6K-2 
Page
Cylinder Block and Cylinder Head 6K-2
Hot Water Heater 6K-2
Fan Belt . 6K-2
Adjustment ....". 6K-2
Thermostat . 6K-2
Replacement 6K-2
Water Pump. . . . 6K-3
Removal 6K-3
Installation 6K-3
GENERAL DESCRIPTION
A pressure cooling system is provided for on all
models by a pressure type radiator cap (fig. 1). The
pressure type radiator cap used is designed to hold a
pressure above atmospheric pressure in the cooling
system. Excessive pressure is relieved by a valve within
the cap that opens to radiator overflow.
The water pump is a ball bearing, centrifugal vane
impeller type. It requires no care other than to make
certain the air vent at the top of the housing and the drain
holes in the bottom do not become plugged with dirt or
grease. Removal and installation of the water pump is
covered in this section. For overhaul procedures of the
water pump refer to Section 6K of the Passenger Chassis
Overhaul Manual. 
For radiator, refer to Section 13 of this manual For
radiator shroud, refer to Section 11 of this manual.
Fig.
 I—Pressure Radiator Cap
MAINTENANCE AND ADJUSTMENTS
Coolant Level
The radiator coolant level should only be checked when
the engine is cool, particularly on cars equipped with air
conditioning. If the radiator cap is removed from a hot
cooling system, serious personal injury may result
The cooling system fluid level should be maintained
one inch below the bottom of the filler neck of the radia-
tor when cooling system is cold, or at the bottom of the
filler neck when the system is warm. It is very impor-
tant that the correct fluid level be maintained. The seal-
ing ability of the radiator cap is affected when the cooling
level is too high.
All passenger car cooling systems are pressurized
with a pressure cap which permits safe engine operation
at cooling temperatures of
 up
 to 247°F.
When the radiator cap is removed or loosened, the
system pressure drops to atmospheric, and the heat
which had caused water temperature to be higher than
212°F, will be dissipated by conversion of water to
steam. Inasmuch as the steam may form in the engine
water passages, it will blow coolant out of the radiator
upper hose and top tank, necessitating coolant replace-
ment Engine operating temperatures higher than the
normal boiling point of water are in no way objectionable
so long as the coolant level is satisfactory when the
engine is cooL
Upon repeated coolant loss, the pressure radiator cap
and seat should be checked for sealing ability. Also, the 
cooling system should be checked for loose hose con-
nections, defective hoses, gasket leaks, etc.
Coolant System Checks
1.
 Test for restriction in the radiator, by warming the
engine up and then turning the engine off and feeling
the radiator. The radiator should be hot at the top
and warm at the bottom, with an even temperature
rise from bottom to top. Cold spots in the radiator
indicate clogged sections.
2.
 Water pump operation may be checked by running the
engine while squeezing the upper radiator hose. A
pressure surge should be felt Check for a plugged
vent-hole in pump.
NOTE:
 A defective head gasket may allow ex-
haust gases to leak into the cooling system.
This is particularly damaging to the cooling
system as the gases combine with the water to
form acids which are particularly harmful to
the radiator and engine.
3.
 To check for exhaust leaks into the cooling system,
drain the system until the water level stands just
above the top of the cylinder head, then disconnect
the upper radiator hose and remove the thermostat
and fan belt. Start the engine and quickly accelerate
several times. At the same time note any appreci-
able water rise or the appearance of bubbles which
CHEVROLET CHASSIS SERVICE MANUAL 

ENGINE COOLING 6K-2
are indicative of exhaust gases leaking into the coolr
ing system.
Periodic Maintenance
Periodic service must be performed to the engine cool-
ing system to keep it in efficient operating condition.
These services should include a complete cleaning and
reverse flushing as well as a reconditioning service.
In the course of engine operation, rust and scale ac-
cumulate in the radiator and engine water jacket. The
accumulation of these deposits can be kept to a minimum
by the use of a good rust inhibitor but it should be
remembered that an inhibitor will not remove rust al-
ready present in the cooling system.
Two common causes of corrosion are: (1) air suction--
Air may be drawn into the system due to low liquid level
in the radiator, leaky water pump or loose hose con-
nections; (2) exhaust gas leakage—Exhaust gas may be
blown into the cooling system past the cylinder head
gasket or through cracks in the cylinder head and block.
Cleaning
A good cleaning solution should be used to loosen the
rust and scale before reverse flushing the cooling
system. There are a number of cleaning solutions avail-
able and the manufacturer's instructions with the particu-
lar cleaner being used should always be followed.
An excellent preparation to use for this purpose is GM
Cooling System Cleaner. The following directions for
cleaning the system applies only when this type cleaner
is-used.
1.
 Drain the cooling system including the cylinder block
and then close both drain plugs.
2.
 Remove thermostat and replace thermostat housing.
3.
 Add the liquid portion (No. 1) of the cooling system
cleaner.
4.
 Fill the cooling system with water to a level of about
3 inches below the top of the overflow pipe.
5. Cover the radiator and run the engine at moderate
speed until engine coolant temperature reaches 180
degrees.
6. Remove cover from radiator and continue to run the
engine for 20 minutes. Avoid boiling.
7. While the engine is still running, add the powder
portion (No. 2) of the cooling system cleaner and
continue to run the engine for 10 minutes.
8. At the end of this time, stop the engine, wait a few
minutes and then open the drain cocks or remove
pipe plugs. Also remove lower hose connection.
CAUTION: Be careful not to scald your hands.
NOTE:
 Dirt and bugs may be cleaned out of
the radiator air passages by blowing out with air
pressure from the back of the core.
Reverse Flushing
Reverse flushing should always be accomplished after
the system is thoroughly cleaned as outlined above.
Flushing is. accomplished through the system in a direc-
tion opposite to the normal flow. This action causes the
water to get behind the corrosion deposits and force
them out.
Radiator
1.
 Remove the upper and lower radiator hoses and re-
place the radiator cap,
2.
 Attach a lead-away hose at the top of the radiator. 
3.
 Attach a new piece of hose to the radiator outlet
connection and insert the flushing gun in this hose.
4.
 Connect the water hose of the flushing gun to a water
outlet and the air hose to an air line.
5. Turn on the water and when the radiator is full, turn
on the air in short blasts, allowing the radiator to
fill between blasts of air.
CAUTION: Apply air gradually as a clogged
radiator will stand only a limited pressure.
6. Continue this flushing until the water from the lead-
away hose runs clear.
Cylinder Block and Cylinder Head
1.
 With the thermostat removed, attach a lead-away
hose to the water pump inlet and a length of new hose
to the water outlet connection at the top of the engine.
NOTE:
 Disconnect the heater hose when re-
verse flushing engine.
2.
 Insert the flushing gun in the new hose.
3.
 Turn on the water and when the engine water jacket
is full, turn on the air in short blasts.
4.
 Continue this flushing until the water from the lead-
away hose runs clear.
Hot Water Heater
1.
 Remove water outlet hose from heater core pipe.
2.
 Remove inlet hose from engine connection.
3.
 Insert flushing gun and flush heater core. Care must
be taken when applying air pressure to prevent
damage to the core.
Fan Belt
Adjustment
1.
 Loosen bolts at Delcotron slotted bracket.
2.
 Pull Delcotron away from engine until desired ten-
sion reading is obtained with a strand tension gauge.
Refer to Section 6, "Engine Tune-Up".
3.
 Tighten all Delcotron bolts securely.
Thermostat
The thermostat consists of a restriction valve actuated
by a thermostatic element. This is mounted in the hous-
ing at the cylinder head water outlet above the water
pump,
 thermostats are designed to open and close at
predetermined temperatures and if not operating properly
should be removed and tested as follows.
Replacement
1.
 Remove radiator to water outlet hose.
2.
 Remove thermostat housing bolts and remove water
outlet and gasket from thermostat housing (fig. 2).
3.
 Inspect thermostat valve to make sure it is in good
condition.
4.
 Place thermostat in hot water 25° above the temper-
ature stamped on the thermostat valve.
5. Submerge the valve completely and agitate the water
thoroughly. Under this condition the valve should
open fully.
6. Remove the thermostat and place in water 10° below
temperature indicated on the valve.
7. With valve completely submerged and water agitated
thoroughly, the valve should close completely.
8. If thermostat checks satisfactorily, re-install, using
a new housing gasket.
9. Refill cooling system.
CHEVROLET CHASSIS SERVICE MANUAL 

ENGINE FUEL 6M-9
4.
 Wash body with cleaning solvent and wip dry.
5. Wash filter element by sloshing up and down in
cleaning solvent.
6. Dry filter unit with an air hose or let stand until
dry.
7. Fill body of cleaner to full mark with SAE 50 engine
oil. If expected temperatures are to be consistently
below freezing, use SAE 20 engine oil.
8. Assemble filter and cover assembly to body of
cleaner.
9. Install cleaner, making sure it fits tight and is set
down securely. \
OIL
 WETTED
 PAPER
 ELEMENT
Replacement
1.
 Remove wing nut, washer and cover.
2.
 Remove paper element and discard.
3.
 Remove bottom section of air cleaner and gasket
on air horn of carburetor. Discard air horn gasket.
4.
 Clean bottom section of air cleaner and cover pieces
thoroughly, to remove dust and grime.
NOTE:
 Check bottom section of air cleaner
seal for tears or cracks.
5. Install a new gasket on carburetor air horn and set
bottom section of air cleaner on carburetor.
6. Install new paper element on bottom section of air
cleaner with either end up.
NOTE:
 Plastisol seal is the same material on
both ends.
7. Install cover, washer and wing nut.
Testing (Fig. 5A)
Tool J-7825, is designed to check paper element air
cleaners to determine whether the element has ma-
terially decreased in efficiency arid should be replaced
or has only slightly increased air restriction and is
suitable for further service. In combination with a
tachometer, this instrument will quickly and accurately
determine the air cleaner element condition.
VENT HOLE
TOWARD DASH 
NOTE:
 t Before testing, inspect for holes or
breaks in the element, as these defects re-
quire immediate replacement. If no holes or
breaks exist, proceed as follows:
1.
 Remove all hoses and plug all openings except air
cleaner inlet.
2.
 Install air cleaner, using Tool J-7825 in place of the
wing nut. Screw Tool J-7825 onto the stud until it
seals tightly against the air cleaner cover. Rotate
the entire tool so that the scale can be read from
the left side of the car. Be sure the vent hole is
toward the dash.
3.
 Connect a tachometer and place it so that it may be
read simultaneously with Tool J-7825.
4.
 Zero oil level in the inner tube by pulling inner tube
upward until the rubber seal is above the vent hole,
then raise or lower as' required until the inner tube
oil level is exactly to the "0" mark.
5. Start engine. If engine is cold, allow to run for 2 to
3 minutes. The automatic choke must be fully open.
6. Accelerate the engine slowly until the inner tube oil
level of Tool J-7825 just reaches the 1/4 mark.
Allow engine speed to stabilize and note tachometer
(rpm) reading. Decelerate engine.
7. If the tachometer reading is at or below the follow-
ing, the oil wetted paper air cleaner element is re-
stricted beyond the allowable limit and should be
replaced. If testing indicates that the element
restriction is satisfactory at 12,000 miles, the ele-
ment need not be replaced but should be retested
every 6,000 miles thereafter until replaced.
Engine
Displacement
283 cu.
 in.
327 cu.
 in.
350 cu. in.
396 cu.
 in.
427 cu.
 in. 
Horsepower
195
210
275
300
325
350
295
325
350
385
390
425 
Minimum
Allowable
RPM
2300
2100
210Q
2600
2600
1550
1950
1850
1850
2140
Fig.
 5A—Testing Air Cleaner 
8. Remove tachometer and Tool J-7825 from vehicle
and push down inner tube until seal is below vent
hole to prevent oil loss.
Tool J-7825
FiHing
 Tool
Tool J-7825 is shipped dry and must be filled with the
red gauge oil (specific gravity .826) provided.
Pull the knurled inner tube completely out of the gauge
and add oil to the reservoir until the oil level is between
CHEVROLET CHASSIS SERVICE /MANUAL 

ENGINE FUEL
 6M-10
the
 two
 "FILL71 lines
 (fig.
 6A). Refill whenever
 the
 level
falls below the lower
 <'FILL"
 line.
Storing Tool
When
 the
 tool
 is
 not used, fully depress
 the
 inner tube.
This seals
 off
 the
 oil
 reservoir from the vent hole
 to pre-
vent
 oil
 loss
 if
 the tool
 is
 tipped.
Fig. 6A-Filling Tool with
 Oil
FUEL PUMP
INDEX
Page
General Description
 . . . . 6M-10
Service Procedures .6M-10
Inspection .6M-10 
Page
Test
 . . ; 6M-10
Removal
 6M-11
Installation
 6M-11
GENERAL DESCRIPTION
The fuel pump
 (fig. IP)
 used
 on all
 Chevrolet vehicles
covered
 in
 this manual
 are of the
 diaphragm type.
 The
pumps
 are
 actuated
 by an
 eccentric located on
 the
 engine
camshaft.
 On
 in-line engines,
 the
 eccentric actuates
 the
rocker arm*
 On V-8
 engines,
 a
 push
 rod
 (located be-
tween
 the
 camshaft eccentric and fuel pump) actuates
 the
pump rocker
 arm.
 Because
 of
 design, this pump
 is
serviced
 as an
 assembly only.
Fig.
 IP—Fuel Pump (Non-Serviceable)
SERVICE PROCEDURES
Inspection
The fuel pump should
 be
 checked
 to
 make sure
 the
mounting bolts
 and
 inlet and outlet connections
 are
 tight.
Test
Always test pump while
 it is
 mounted on the engine
 and 
be sure there
 is
 gasoline
 in
 the tank.
The line from
 the
 tank
 to the
 pump
 is the
 suction side
of
 the
 system and the line from the pump
 to the
 carbure-
tor
 is the
 pressure side
 of the
 system.
 A
 leak on
 the
pressure side, therefore, would
 be
 made apparent
 by
CHEVROLET CHASSIS SERVICE MANUAL 

CLUTCH AND TRANSMISSIONS 7-3
DETENT CAM
DETENT SPRING
DETENT CAM
2-3 SHIFT
FORK
DETENT CAM
PIVOT PIN
1ST & REV. 1ST& REV.
SHIFTER SHAFT SHIFT FORK
DETENT CAM
RETAINER RING 
2-3 SHIFTER SHAFT
Fig. 3A
 •*
 Transmission Side Cover, Shift Fork and Detent Assembly
5. Reinstall propeller shaft and any items removed to
obtain clearance.
TRANSMISSION SIDE COVER
Removal •
1.
 Disconnect control rods from levers; remove 2-3
cross shaft (Chevrolet)
2.
 Shift transmission into neutral detent positions before
removing cover.
3.
 Remove cover assembly from transmission case
carefully and allow oil to drain. 
Disassembly (Fig. 3A)
1.
 Remove the outer shifter levers.
2.
 Remove both shift forks from shifter shaft assem-
blies.
 Remove both shifter shaft assemblies from
cover. "OM ring seals around shifter shaft may now
be pryed out if replacement is required because of
damage.
3.
 Remove detent cam spring and pivot retainer "C"
ring. Remove both detent cams.
4.
 Replace damaged parts.
Assembly (Fig. 3A)
1.
 With,
 detent spring tang projecting up over the
 2nd
 and
3rd shifter shaft cover opening install the first and
reverse detent cam onto the detent cam pivot pin.
With the detent spring tang projecting up over the
first and reverse shifter shaft cover hole install the
2nd an£ 3rd detent cam.
2.
 Install detent cam retaining "C" ring to pivot shaft,
and hook spring into detent cam notches.
3.
 Install both shifter shaft assemblies in cover being
careful not to damage seals. Install both shift forks
to shifter shaft assemblies^ lifting up on detent cam
to allow forks to fully seat into position.
4.
 Install outer shifter levers, flat washers, lock wash-
ers and bolts.
Installation
1.
 Shift shifter levers into neutral detent (center) posi-
tion.
 Position cover gasket on case.
2.
 Carefully position side cover into place making sure'
the shift forks are aligned with their respective
mainshaft clutch sliding sleeves.
3.
 Install cover attaching bolts and tighten evenly to
specified torque.
4.
 Remove filler plug and add lubricant specified in
Section 0, to level of filler plug hole.
COMPONENT PART REPLACEMENT
TRANSMISSION REPLACEMENT (EXC. CORVETTE)
Removal From Vehicle
1.
 Remove propeller shaft assembly.
2.
 Disconnect speedometer cable at transmission.
3.
 Disconnect shifter rods at transmission levers.
4.
 Support engine assembly.
5. Remove transmission to clutch housing bolts.
6. Remove transmission crossmember to mount bolts.
7. Loosen transmission crossmember and move rear-
ward or remove.
8. Slide transmission rearward and remove.
Installation in Vehicle
1.
 Raise transmission into position and slide forward
piloting clutch gear retainer into clutch housing.
2.
 Install transmission to clutch housing retaining bolts
and lock washers, torque to 50 ft. lbs.
3.
 Repositioning transmission crossmember and install
retaining bolts.
4.
 Install transmission crossmember to mount bolts.
5. Connect and adjust shift rods at transmission levers
and cordon shaft to 2nd and 3rd lever on Chevrolet
Models. (Fig. 4A) 
Fig. 4A - Chevrolet 2-3 Shift Lever Cordon Shaft
CHEVROLET CHASSIS SERVICE MANUAL 

CLUTCH AND TRANSMISSIONS 7-19
2.
 With handle in full down position—adjust cable to ac-
quire dimension shown, be certain that cable is pulled
taut.
3.
 Tighten set screw to 15-20 in. lbs.
4.
 Bend excess wire and cut - be certain that wire does
not interfere with I.D. of lever or threads of shifter
knob.
NOTE: Handle must return freely from any
position.
SPEEDOMETER DRIVEN GEAR AND OIL SEAL
Replacement
Disconnect speedometer cable, remove retainer to
housing bolt and lock washer and remove retainer. In-
sert screw driver in slot in fitting and pry fitting, gear
and shaft from housing. Pry "O" ring in groove in fitting.
Install new "O" ring in groove and insert shaft Hold
the assembly so slot in fitting is toward boss on housing
and install in housing. Push fitting into housing until re-
tainer can be inserted in groove and install retainer lock
washer and bolt. 
Fig.
 5M - Installing Side Cover Assembly
TRANSMISSION SIDE COVER
Removal
1.
 Disconnect control rods from levers.
2.
 Shift transmission into second speed before removing
cover, by moving 1-2 (Rear Cover) shifter lever into
forward detent position.
3.
 Remove cover assembly -from transmission case
carefully and allow oil to drain.
Disassembly (Fig. 4M)
1.
 Remove the outer shifter lever nuts,*lock washers
and flat washers. Pull levers from shafts.
2.
 Remove both shift forks from shifter shaft and detent
plate assemblies. Remove both shifter shaft assem-
blies from cover. Lip seals in side cover may now
be pryed out if replacement is required because of
damage.
1-2 DETENT CAM DETENT SPRING 
3-4 DETENT CAM
1-2 SHIFTER SHAFT
1-2 SHIFT FORK 
3-4 SHIFT
FORK
DETENT CAM \ 3-4 SHIFTER SHAFT
RETAINER RING
DETENT CAM PIVOT PIN 
3.
 Remove detent cam spring and pivot retainer "C"
ring. Remove both detent cams.
4.
 Replace necessary parts.
Assembly (Fig. 4M)
1.
 Install 1-2 detent cam to cover pivot pin first, then
install 3-4 detent cam so the detent spring notches
are offset or opposite each other. Detent cam
notches must be facing downward.
2.
 Install detent cam retaining "C" ring to pivot shaft,
and hook spring into detent cam notches.
3.
 Install both shifter shaft assemblies in cover being
careful not to damage lip seals. Install both shift
forks to detent plates, lifting up on detent cam to
allow forks to fully seat into position.
4.
 Install outer shifter levers, flat washers, lock wash-
ers and nuts.
Installation (Fig. 5M)
1.
 Shift 1-2 shifter lever into second speed (forward)
position. Position cover gasket on case.
2.
 Carefully position side cover into place making sure
the shift forks are aligned with their respective
mainshaft clutch sliding sleeves.
3.
 Install cover attaching bolts and tighten evenly to
15-20 ft. lbs. torque.
4.
 Remove filler plug and add lubricant specified in
Section 0, to level of filler plug hole.
EXTENSION OIL SEAL
Replacement
1.
 Remove propeller shaft.
2.
 Pry out the extension oil seal.
3.
 Prelubricate between sealing lips and press new oil
seal carefully into place in extension using J-5154 or
similar tool.
Fig.
 4M - Transmission Side Cover/ Shift Fork and
Detent Assembly 
CAUTION: Do not excessively force the seal
against the seat in the extension.
CHEVROLET CHASSIS SERVICE MANUAL 

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 

CLUTCH
 AND
 TRANSMISSIONS
 7-23
Assembly (Fig.
 4X)
1.
 With detent spring tang projecting
 up
 over
 the 3rd
and
 4th
 shifter shaft cover opening install
 the
 first
and second detent
 cam
 onto
 the
 detent
 cam
 pivot
 pin.
With
 the
 detent spring tang projecting
 up
 over
 the
first
 and
 second shifter shaft cover hole install
 the
3rd
 and 4th
 detent
 cam,
NOTE:
 The 1-2
 detent
 cam has a
 .090" greater
contour
 on the
 inside detent notch.
2.
3. 
Install detent
 cam
 retaining
 "C"
 ring
 to
 pivot shaft,
and hook spring into detent
 cam
 notches.
Install
 1-2 and 3-4
 shifter shaft assemblies
 in
 cover
being careful
 not to
 damage seals. Install both shift
forks
 to
 shifter shaft assemblies, lifting
 up on
 detent 
cam
 to
 allow forks
 to
 fully seat into position.
4.
 Install reverse detent ball
 and
 spring
 to
 cover, then
install reverse shifter shaft assembly
 to
 cover.
5.
 Install outer shifter levers, flat washers, lock wash-
ers
 and
 bolts.
Installation
1.
 Shift shifter levers into neutral detent (center) posi-
tion. Position cover gasket
 on
 case.
2.
 Carefully position side cover into place making sure
the shift forks
 are
 aligned with their respective
mainshaft clutch sliding sleeves.
Install cover attaching bolts
 and
 tighten evenly
 to
specified torque.
Remove filler plug
 and add
 lubricant specified
 in
Section
 0, to
 level
 of
 filler plug hole.
3.
4.
ALUMINUM POWERGLIDE
INDEX
Page
General
 Description
 7-23
Maintenance
 and
 Adjustments .............. 7—23
Oil
 Level Check
 7-23
Periodic
 Oil
 Change
 7-24
Periodic
 Low
 Band Adjustment
 7-24
Manual
 Shift Linkage Check
 and
 Adjust
 7-24
Floor
 Shift Linkage
 7-25
Floor
 Mounted Control Lever
 and
Bracket
 Assembly
 7-29
Throttle
 Valve Linkage
 .... 7-29
Neutral
 Safety Switch
 .. . 7-30
Throttle
 Return Check Valve (Dashpot)
 7-30
Component
 Parts Replacement
 7-30
Transmission
 Replacement .............. 7—30 
Page
Other
 Service Operations
 7-32
Diagnosis
 7-32
Warming
 Up
 Transmission
 7-32
Shop
 Warm
 Up , 7-32
Road
 Warm
 Up 7-32
Checking
 Fluid Level
 and
 Condition
 7-32
Manual
 Linkage
 7-32
Oil
 Leaks
 7-33
Basic
 Pressure Checks
 7-33
Wide
 Open Throttle Upshift Pressure Check
 .... 7-33
Idle
 Pressure
 in
 Drive Range
 7-33
Manual
 "Low"
 Range Pressure Check .......
 7-33
Drive
 Range Overrun (Coast) Pressure
 .
 .......
 7-33
Powerglide
 Shift Points
 . . 7-35
GENERAL DESCRIPTION
The case
 and
 converter housing
 of the two
 speed alumi-
num Powerglide Transmission
 is a
 single case aluminum
unit. When
 the
 manual control
 is
 placed
 in the
 drive
 po-
sition,
 the
 transmission automatically shifts
 to low
 gear
for initial vehicle movement.
 As the car
 gains speed
 and
depending
 on
 load
 and
 throttle position,
 an
 automatic shift
is made
 to
 high gear.
 A
 forced downshift feature
 pro-
vides
 a
 passing gear
 by
 returning
 the
 transmission
 to low
range.
The
 oil
 pump assembly
 is a
 conventional gear type
 and
the
 oil
 pump housing
 is of the
 large diameter type acting
as
 the
 front bulkhead
 of the
 transmission.
 The
 torque
converter
 is a
 conventional three element welded design
bolted
 to the
 engine flywheel which drives through
 a
 two-
speed planetary gearset.
 The
 high clutch assembly
 is
typical
 of the
 designs used
 in
 this type transmission.
 The
aluminum Powerglide uses
 an
 output shaft mounted
 gov- 
ernor which requires
 a
 hole through
 the
 output shaft.
 The
reverse clutch assembly
 is a
 multiple disc type clutch.
The steel plates
 are
 splined directly
 to the
 case while
 the
face plates
 are
 splined
 to the
 internal
 or
 ring gear.
 The
clutch piston operates within
 the
 rear portion
 of the
 case.
The internal diameter
 of the
 pistoh
 is
 sealed to
 an
 integral
hub portion
 of the
 case rear bulkhead.
 The
 outside
 dia-
meter
 is
 sealed
 to a
 machined portion
 of the
 case.
 The
piston
 is
 hydraulically applied
 and is
 released
 by
 separate
coil springs.
 The
 valve body assembly
 is
 bolted
 to the
bottom
 of the
 transmission case
 and is
 accessible
 for
service
 by
 removing
 the oil pan
 assembly.
 The
 valve
body consists
 of an
 upper
 and
 lower body located
 on
 either
side
 of a
 transfer plate.
 The
 vacuum modulator
 is lo-
cated
 on the
 left rear face
 of the
 transmission case.
 The
modulator valve bore
 is
 located
 in the
 upper valve body.
MAINTENANCE
 AND
 ADJUSTMENTS
OIL LEVEL CHECK
The transmission
 oil
 level should
 be
 checked period-
ically
 as
 recommended
 in
 Section
 0. Oil
 should
 be
 added
only when level
 is on or
 below
 the
 "ADD" mark
 on the dip
stick with
 oil hot or at
 operating temperature.
 The oil
level
 dip
 stick
 is
 located
 at the
 right rear
 of the
 engine 
compartment. Fill with
 oil
 specified
 in
 Section
 0.
In order
 to
 check
 oil
 level accurately,
 the
 engine should
be idled with
 the
 transmission
 oil hot and the
 control
lever
 in
 neutral (N) position.
It
 is
 important that
 the oil
 level
 be
 maintained
 no
higher than
 the
 "FULL" mark
 on the
 transmission
 oil
level gauge.
 DO NOT
 OVERFILL,
 for
 when
 the oil
 level
CHEVROLET CHASSIS SERVICE MANUAL