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