CLUTCH AND TRANSMISSIONS 7-5
CHEVY II
Fig.
6 - Lower Linkage Details (Chevrolet, Chevelle & Chevy II)
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-6
L6 ENGINE
V8 ENGINE
Fig.
7 - Lower Linkage Details - Camaro
Fig.
8 - Corvette Lower Linkage Details
THREE-SPEED (SA6INAW FULLY SYNCHRONIZED)
TRANSMISSION
General Description . .
Maintenance and Adjustments
Shift Linkage Adjustment
Shift Control Lever
&
Bracket Assembly
Speedometer Driven Gear ..........
INDEX
Page Page
7-6 Extension Oil Seal Replacement 7-7
7-7 Transmission Side Cover 7-8
7-7 Component Part Replacement 7-8
7-7 Transmission Replacement (exc. Corvette) . 7-8
7-7 Corvette Transmission Replacement 7-9
GENERAL DESCRIPTION
The Saginaw three 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 located
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 between the
counter and clutch gears to reduce torsional vibrations.
The reverse idler gear is carried on a bushing finish
bored in place. It rotates on a short idler shaft with a
steel thrust washer tanged into the case against the rear
face. Forward movement is stopped by a snap ring on
the idler shaft.
Gear shifting is manual through shift control rods to
the rearward shift lever of the side cover assembly for
first and reverse gear; and through a cross shaft assem-
bly (Chevrolet models) attached to the forward side cover
lever for second and third gear. All three forward gears
are fully synchronized. 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.
The transmission may be used as an aid in deceleration
by downshifting in sequence without double-clutching or
any gear clashing. Reverse is not- synchronized, how-
ever, it is a helical gear to insure quiet operation.
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-7
MAINTENANCE AND ADJUSTMENTS
CHEVROLET, CHEVELLE, CHEVY II, CAMARO,
SHIFT LINKAGE ADJUSTMENT
In cases where the gearshift linkage has been discon-
nected, it should be adjusted as follows:
1.
Move both transmission shift levers until transmis-
sion is in neutral. Neutral detents in transmission
cover must both be engaged to make this adjustment
correctly. (To check, start engine with clutch dis-
engaged, and release clutch slowly.)
2.
Move selector lever to neutral position. Align first
and reverse tube lever with the second and third
shifter tube lever on the mast jacket. This may be
done by having an assistant hold the mast .jacket shift
levers aligned in neutral position or use a simple
gauge or pin to align these levers in neutral.
3.
Make necessary adjustment to align shift control
rods and transmission levers in neutral position.
Move selector lever through all positions to check ad-
justment and to insure over-travel in all positions.
FLOOR SHIFT LINKAGE ADJUSTMENT
1.
Set Transmission Levers (K) and (L) in neutral de-
tent position.
2.
Move Transmission Control Lever (A) to neutral de-
tent and insert Locating Pin (D) into notch of Lever
and Bracket Assembly.
3.
Install Nut (N) and Clevis (M) on Rod (J) loosely,
attach Rod to Lever (B) and secure with retainer.
4.
With Lever (B) against Locating Pin, adjust Clevis
at Lever (L) until Clevis pin passes freely through
holes and secure with washer and cotter pin. Tighten
Nut (N).
5.
Install Nuts (E) and (G) and Swivel (F) loosely on Rod
(H),
attach Rod to Lever (K) and secure with retainer.
6. With Lever (C) against Locating Pin, attach Swivel to
lever and secure with retainer. iRun Nut (G) against
Swivel, then tighten Nut (E) against Swivel.
7.
Remove Locating Pin and check shifts to insure
proper operation. Readjust clevis and swivel if nec-
essary.
LEVER (A)
LEVER (L) CLEVIS (M)-NUT (N
LEVER (C)
ROD(J).
" - -
LEVER (K) ROD (H)^ NUT '(G) SWIVEL (F) ^NUT (E)
SHIFT CONTROL LEVER AND BRACKET ASSEMBLY
If disassembly of this control lever and bracket assem-
bly is necessary refer to Figure 2A for parts breakdown
and relative positioning for assembly.
SPEEDOMETER DRIVEN GEAR
Disconnect speedometer cable, remove lock plate to ex-
tension bolt and lock washer and remove lock plate. In-
sert screwdriver in lock plate slot in fitting and pry fitting
gear and shaft from extension. Pry "O" ring from groove
in fitting.
Install new "OM 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 extension and install in extension. Push fitting
into extension until lock plate can be inserted in groove
and attach to extension.
EXTENSION OIL SEAL REPLACEMENT
.1.
Remove propeller shaft as outlined in Section 4 and
disconnect any necessary items to obtain clearance.
2.
Pry seal out of extension.
3.
Wash counterbore with cleaning solvent and inspect
for damage.
4.
Prelubricate between sealing lips and coat new seal
O.D. with Permatex or equivalent and start straight
in bore in case extension. Using Tool J-5154, tap
seal into counterbore until flange bottoms against
extension.
Fig.
1A- Shift Linkage Adjustment (Typical)
Fig.
2A - Corvette 3 Speed Control Lever and Bracket Assembly
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 7-9
6. Connect speedometer cable.
7. Install propeller shaft assembly.
8. Fill transmission with lubricant specified in Section
O.
CORVETTE TRANSMISSION REPLACEMENT
, 1. Disconnect battery ground cable.
2.
Pisassemble transmission shift control lever by un-
screwing ball from lever, lifting out
"T"
handle re-
turn spring and "T" handle, then remove the anti-
rattle bushings.
3.
Raise front and rear of vehicle.
4.
Insert a block of wood between the top of the dif-
ferential carrier housing and the underbody (to pre-
vent upward travel of the carrier when the carrier
front support is disconnected).
5. Disconnect the differential carrier front supportfrom
its frame bracket, by removing the nut on the under-
side of the biscuit mount.
6. Pry the carrier downward to relieve load while re-
moving the two center mounting bolts from the car-
rier front support. (To pry carrier downward insert
crowfoot end of a pry bar through the opening in the
carrier front support, hooking end of bar over top of
the center mounting bolt pad cast in the underside of
the carrier.)
7. Pivot carrier support downward for access to prop
shaft "U" joint.
8.
.
Disconnect prop shaft front and then rear "U" bolts.
9. Disconnect parking brake cable from ball socket at
idler lever located near center of underbody.
10.
Remove prop shaft by moving shaft forward.
11.
Remove heat deflectors from the right and left ex-
haust pipe.
12.
Remove left bank exhaust pipe.
13.
Remove right bank exhaust pipe and heat riser.
14.
Disassemble the transmission mount, as follows:
a. Remove the two bolts that attach rear mount
cushion to the rear mount bracket.
b.
Support engine under oil pan and raise engine to
remove load from rear mount cushion.
CAUTION: To avoid damage to oil pan, a suit-
able wide base, heavy wood platform should be
placed between the jack pad and the oil pan.
c. Remove the three transmission mount bracket-
to-
crossm ember bolts and remove mount bracket.
d. Remove the two bolts from mount pad to trans-
mission case and remove rubber mount cushion
and exhaust pipe "yoke".
15.
Disconnect transmission linkage by removing the
shift levers at the transmission side cover.
16.
Disconnect speedo cable at transmission extension.
17.
Remove transmission output shaft slip yoke.
NOTE:
The yoke is removed to avoid tearing
the heat reflecting pad on the underbody, when
the transmission is being removed.
18.
Remove two bolts to disconnect the transmission
gearshift control lever and bracket assembly from
its adapter plate on side of transmission. Lower
transmission assembly from the vehicle, letting the
gearshift lever slide down and through the dust boot
in the console.
19.
Remove transmission-to-clutch housing attaching
bolts.
20.
Slide transmission assembly rearward from clutch
and rotate transmission for access to the three flat
head machine screws in the control lever bracket
adapter plate. Remove adapter plate. Rotate trans-
mission back to the upright position.
21.
To allow room for transmission removal slowly
lower the rear of engine until the tachometer drive
cable at the distributor just clears the horizontal
ledge across the front of dash.
CAUTION: The tachometer cable can be easily
damaged by heavy contact with the dash. Slide
transmission rearward out of the clutch, then
tip front end of transmission downward and
lower the assembly from vehicle.
22.
Reinstall transmission assembly by performing above
steps in reverse order.
TRANSMISSION OVERDRIVE
INDEX
Page
General
Description 7-10
Maintenance
and Adjustments 7—10
Governor
Switch and Pinion .............. 7-10
Sun
Gear Solenoid Oil Seal and Control
Cable
Bracket 7-10
Case
Rear Oil Seal 7-10
Removal
7-10
Installation
. . . . . 7-10
Control
Shaft Lever and Oil Seal 7-10
Speedometer
Driven Gear 7-10
Electrical
Unit Checks 7-11
Overdrive
Relay . 7-11
Page
Air
Gap 7-11
Point
Opening 7-11
Closing
Voltage 7-11
Solenoid
. 7-11
Closing
Coil 7-11
Engaging
Spring . - 7-11
Ignition
Grounding Contact . 7-11
Governor
Switch 7-11
Kickdown
Switch 7-11
Diagnosis
- Overdrive 7-12
Mechanical
. 7-12
Electrical
7-13
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-10 ,
GENERAL DESCRIPTION
The overdrive unit is essentially a two-speed planetary-
transmission attached to the rear of a conventional three-
speed transmission. In overdrive, engine speed is ap-
proximately 30 per cent slower at a given road speed
since the drive train includes planetary gears which pro-
vide a lower overall gear ratio than that obtained in high
gear with the conventional transmission.
The electrical equipment which controls the automatic
action of the mechanical portion of the overdrive unit
consists of a solenoid, a speed-sensitive governor switch,
a relay and a kickdown switch. The circuit including this
equipment makes it possible to operate in overdrive above
a pre-set cut-in speed, or in .conventional drive at any
speed.
With the overdrive unit engaged, the transmission
should not be left in any forward gear with intent of lock-
ing the drive-line as the overrunning clutch is a free-
wheeling condition.
SERVICING THE OVERDRIVE
With the,overdrive assembly removed from the trans-
mission, service operations on the transmission proper
are the same as for the standard three-speed trans-
mission.
Repairs to the overdrive housing, output shaft, ring
gear assembly, clutch cam, roller retainer, pinion cage,
sun gear, shift rail, sun gear control plate, output shaft
bearing, oil seal, speedometer drive gear, solenoid pawl
and interlock plunger may be performed underneath the
car, if so desired, by removing the overdrive housing
without disturbing the transmission. Refer to Overhaul
Manual for Service Procedure.
If the transmission mainshaft, overdrive adapter or
transmission rear bearing which is retained in adapter
require replacement, the entire transmission and over-
drive assembly should be removed and overhauled on the
bench.
MAINTENANCE AND ADJUSTMENTS
Servicing of the overdrive governor switch and pinion,
the sun gear solenoid, oil seal and cable bracket, the out-
put shaft rear oil seal, the control shaft lever, and the
speedometer driven gear may be accomplished without
removing the overdrive from the vehicle, as discussed
in the following paragraphs:
GOVERNOR SWITCH AND PINION
To remove governor switch, disconnect wires at gover-
nor switch and screw governor
out
of housing, using Tool
J-4653 on the flat hexagonal surface of governor case.
The pinion may be separated from the governor by re-
moving the snap ring on the shaft.
SUN GEAR SOLENOID, OIL SEAL AND
CONTROL CABLE BRACKET
Remove the solenoid by taking out the two mounting
bolts and lock washers, removing
the.
cable bracket with
the lower bolt. Turn the solenoid 1/4 turn and
pull,
sole-
noid plunger out of adapter. The oil seal may be pried
out of the adapter.
CASE REAR OIL SEAL
Removal
1.
Remove propeller shaft as outlined in Section 4.
2.
Using a punch against seal in housing, pry out seal
from housing.
Installation
1.
Prelubricate between sealing lips and coat outside of
new oil seal with a suitable sealant, then start seal
into bore in overdrive housing.
2.
Using Tool J-5154 drive oil seal into counterbore.
3.
Install propeller shaft as outlined in Section 4.
CONTROL SHAFT LEVER AND/OR "O" RING
OIL SEALS
To remove- the control shaft, disconnect the cpntrol
cable, remove tapered pin and pull lever out. Replace
the two "0" ring seals on the control shaft. Insert shaft
and new "O" ring seals into housing and install tapered
pin. Connect control wire to lever.
SPEEDOMETER DRIVEN GEAR
Disconnect speedometer cable, remove lock plate to
housing bolt and lock washer and remove lock plate. In-
sert screw driver in lock plate slot in fitting and pry
fitting, gear and shaft from housing. Pry "O" ring from
groove in guide.
Install new "O" ring in groove in fitting and insert
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.
L
dl
ZAIR GAP
km (CHECK WITH
M*= POINTS BARELY
'A
AoWER
|^
POINT
0 ADJUST
=^ i
SUPPORT
Fig. IB - Checking Relay Air Gap
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-11
UPPER ARMATURE STOP
(BEND TO ADJUST POINT OPENING)
Fig.
2B-Adjusting Relay Point Opening
ELECTRICAL UNIT CHECKS
Overdrive Relay
Specifications and checking procedures for this relay
are as follows:
Specifications
Air Gap Oil inch minimum
Point Opening .025 inch
Closing Voltage
8.3-10.2
volts
Armature Sealing Voltage. ..... 11.2 volts maximum
Three checks and adjustments are required on the
overdrive relay; air gap, point opening and closing volt-
age.
The air gap contact point opening checks and adjust-
ments should be made with the battery disconnected.
Air Gap
The air gap should not normally require adjustment
unless the relay has been misadjusted. Check the air gap
with the points barely touching and adjust if necessary by
bending the lower point support (fig, IB).
Point Opening
Check the contact point opening and adjust by bending
the upper armature stop (fig. 2B).
Closing Voltage
To check the relay closing voltage, connect a potenti-
ometer or variable resistance of sufficient value (not less
than 50 ohms) in series with the "KD" terminal, connect a
voltmeter to the "IGN" and "KD" terminals. With the
ignition switch on, slowly decrease the amount of resist-
ance in order to check the relay closing voltage (the
overdrive solenoid and relay should click when the relay
closes). Adjust the closing voltage by bending the arma-
ture spring post (fig. 3B). Bend down to increase the
closing voltage and bend up to decrease the closing
voltage.
To check the sealing voltage, increase the voltage after
the relay closes until the armature seals against the
core.
Decrease the sealing voltage by reducing the relay
air gap.
Solenoid
Closing Coil
Remove solenoid from transmission, connect a jumper
wire between negative terminal of battery and mounting
flange of solenoid. Connect a second jumper wire be-
ARMATURE SPRING PQST
(BEND TO ADJUST CLOSING VOLTAGE)
Fig.
3B - Adjusting Relay Closing Voltage
tween the battery positive terminal and solenoid terminal
No.
4; this should cause the solenoid pawl to move out.
If solenoid chatters, Hold-In Coil is defective.
Engaging Spring
With jumper wire connected as in paragraph above,
(solenoid energized, plunger extended) place ball end of
solenoid against bench. Push down on solenoid. The
pawl rod should move in 3/8M under a load of not less
than 8 lbs. nor more than 12. Pawl should move out to
extended position when load is removed.
Ignition Grounding Contact
Place a test lamp between negative battery terminal
and solenoid terminal No. 6. Lamp should light when this
connection is made. Remove jumper from between nega-
tive battery terminal and solenoid terminal No. 4. Pawl
rod should snap "in" and test lamp should go out.
Governor Switch
Remove overdrive wire at governor and connect test
lamp between governor overdrive terminal and positive
terminal of battery. Drive car on road or raise on jacks.
The lamp should light at a car speed of between 26 to 30
MPH. Upon decreasing speed, the lamp should go out at
between 28 and 23.5 MPH. The car speed differential
between light "on" and light "off" should be 2 or 3 MPH.
Kickdown Switch
Disconnect the 4 wires at kickdown switch.
1.
Connect test lamp between "SW" terminal and posi-
tive terminal of battery; with switch in normal posi-
tion, lamp should light when "REL" terminal is
grounded but should not light when "IGN" or "SOL"
terminals or switch case is grounded.
2.
Connect test lamp between "IGN" terminal and posi-
tive terminal of battery; with switch stem pushed in,
lamp should light when "SOL" terminal is grounded,
but should not light when "SW" or "REL" terminals
or switch case is grounded.
CHEVROLET CHASSIS SERVICE MANUAL
CLUTCH AND TRANSMISSIONS 7-12
DIAGNOSIS-OVERDRIVE
MECHANICAL
Any one of the following general complaints may be due
to non-standard mechanical conditions in the overdrive
unit:
1.
Does not drive unless locked up manually.
2.
Does not engage, or lock-up does not release.
3.
Engages with a severe jolt, or noise.
4.
Free-wheels at speeds over 30 mph.
These^ troubles may be diagnosed and remedied as de-
scribed in the following paragraphs.
1.
Does not drive unless locked up manually.
a. Occasionally, the unit may not drive the car for-
ward in direct drive, unless locked up by pulling
the dash control. This may be caused by one or
more broken rollers in the roller clutch, the
remedy for which is the replacement of the entire
set of rollers.
b.
This may also be caused by sticking of the roller
retainer upon the cam. This retainer must move
freely to push the rollers into engaging position,
under the pressure of the two actuating springs.
c. Sometimes this is due to slight indentations, worn
in the cam faces by the rollers spinning, remedied
by replacement of the cam.
2.
Does not engage, or lock-up does not release
.. a. Dash control improperly connected—-Unless the
overdrive dash control wire is connected to the
lockup lever on the left side of the overdrive
housing in such a manner as to move the lever
all the way back when the dash control knob is
pushed in, it may hold the shift rail in such a po-
sition as to interlock the pawl against full engage-
ment resulting in a buzzing noise when overdrive
engagement is attempted.
To correctly make this connection, loosen bind-
ing post at lever, pull dash control knob out 1/4",
move lever all the way to the rear, and tighten
binding post.
b.
Transmission and overdrive improperly aligned—
The same symptoms as above may also result
from misalignment, at assembly, of the overdrive
housing to the transmission case, resulting in
binding of the overdrive shift rail, so that the re-
tractor spring cannot move the rail fully forward,
when the dash control knob is pushed in, and the
transmission is not in reverse. Under such con-
ditions, the unit may remain fully locked up.
To test for this, be sure that the transmission
is not in reverse; disconnect the dash control
wire from the lockup lever, and feel the lever for
free forward movement. If the lever can be
moved forward more than 1/4", it indicates that
misalignment probably exists. To correct this,
Jposen the capscrews between the overdrive hous-
ing and transmission case, and tap the adpater
plate and overdrive housing until a position is
found where the rail shifts freely; tighten cap-
screws.
c. Kickdown switch improperly adjusted—The posi-
tion of the kickdown switch should be adjusted,
by means of the two large nuts which clamp the
switch shank, so the switch plunger travels 3/16"
before the throttle lever touches its stop.
Occasionally the large nuts which clamp the
switch through the switch bracket are tightened
sufficiently to bend the switch shank, thus pre-
venting free motion of the switch stem. This may
usually be remedied by loosening the upper of the
two nuts.
d. Improper installation of solenoid—If car cannot
be rolled backward under any circumstances and
there is no relay click when the ignition is turned
on, it probably indicates that the solenoid has
been installed directly, without twisting into the
bayonet lock between solenoid stem and pawl, thus
jamming the pawl permanently into overdrive en-
gagement. If the car will occasionally roll back-
wards, but not always, (and there is no relay click
when the ignition switch is turned on) it may indi-
cate that, upon installation, the bayonet lock was
caught, and the solenoid forcibly twisted into
alignment with the attaching flange, thus shearing
off the internal keying of the solenoid. Under
these circumstances, the end of the solenoid stem
may not catch in the pawl, and upon release of the
solenoid, the pawl will not be withdrawn promptly
from engagement, but simply drift out. If the
solenoid stem end has its two flats exactly facing
the two solenoid flange holes, it will not withdraw
the pawl properly. If the stem can be rotated
when grasped by a pair of pliers, it indicates that
the internal keying has been sheared.
e. Improper positioning of blocker ring—Occasion-
ally, either in assembly at the factory, or in
service operations in the field, the internal parts
of the overdrive unit may have been rotated with
the solenoid pawl removed, causing the blocker
ring to rotate, so that its two lugs are not located
with respect to- the pawl as shown in Figure 12B.
In other words, the solid portion of the blocker
ring may be in alignment with the pawl, which will
prevent fill} engagement of the pawl with the sun
gear control plate/
To test for this condition, remove solenoid
cover, pull dash control knob out, roll car 2 ft.
forward. Push dash control in, turn ignition
switch on. Then ground the "KD" terminal of
relay, and watch movement of center stem of
solenoid. It should not move more than 1/8" when
the solenoid clicks. Then, with the relay terminal
still grounded, shift into low gear, and roll car
forward by hand. Solenoid stem should then move
an additional 3/8", as the pawl engages fully.
These two tests indicate proper blocker action.
Unless both tests are met, the blocker ring is
probably not in the correct position.
3.
Engages with a severe jolt or noise
Insufficient blocker ring friction may cause the ring
to lose its grip on the hub of the sun gear control
plate. Check the fit and tension of the ring as de-
scribed under "Cleaning and Inspection".
4.
Free-wheels at speeds over 30 MPH
If cam roller retainer spring tension is weak the unit
will free wheel at all times. Check spring action as
described under "Cleaning and Inspection".
CHEVROLET CHASSIS SERVICE MANUAL