differential CHEVROLET CAMARO 1967 1.G Chassis User Guide

REAR SUSPENSION AND DRIVE LINE 4-29

REAR AXLE NOISE DIAGNOSIS

Mechanical failures of the rear axle are relatively

simple to locate and correct. Noise in a rear axle is a

little more difficult to diagnose and repair. One of the

most essential parts of rear axle service is proper

diagnosis.

Ail rear axles are noisy to a certain degree. The

action of transmitting the high engine torque through a

90° turn reducing propeller shaft speed produces noise

in rear axles. This point establishes the need for a line

between normal and abnormal or unacceptable axle

noises.

Slight axle noise heard only at a certain speed or under

remote conditions must be considered normal. Axle noise

tends to "peak" at varying speeds and the noise is in no

way indicative of trouble in the axle.

If noise is present in an objectionable form, loud or at

all speeds, an effort should be made to isolate the noise

as being in one particular unit of the vehicle. Axle noise

is often confused with other noises such as tire noise,

transmission noise, propeller shaft vibration and uni-

versal joint noise. Isolation of the noise as in any one

unit requires skill and experience. An attempt to elimini-

ate a slight noise may baffle even the best of diagnos-

ticians. Such practices as raising tire pressure to

eliminate tire noise, listening for the noise at varying

speeds and on drive, float and coast, and under proper

highway conditions, turning the steering wheel from left

to right to detect wheel bearing noise, will aid even the

beginner in detecting alleged axle noises. Axle noises

fall into two categories: gear noise and bearing noise.

GEAR NOISE

Abnormal gear noise can be recognized since it pro-

duces a cycling pitch and will be very pronounced in the

speed range at which it occurs, appearing under either

"drive," "float" or "coast" conditions. Gear noise

tends to peak in a narrow speed range or ranges, while

bearing noise will tend to remain constant in pitch. Ab-

normal gear noise is rare and usually originates from

the scoring of the ring gear and pinion teeth as a result

of insufficient or improper lubrication in new assemblies.

Side gears seldom give trouble as they are used only

when the rear wheels travel at different speeds.

BEARING NOISE

Defective bearings will always produce a whine that is

constant in pitch and varies with vehicle speed. This fact

will allow you to distinguish between bearing noise and

gear noise.

1.
Pinion bearing noise resulting from a bearing failure

can be identified by a constant rough sound. Pinion

bearings are rotating at a higher speed than differen-

tial side bearings or axle shaft bearings. This

particular noise can be picked up best by testing the

car on a smooth road (black top). However, care

should be taken not to confuse tire noise with bear-

ing or gear noise. If any doubt exists, tire treads

should be examined for irregularities that would

produce such noise.

2.
Wheel bearing noise may be confused with rear axle

noise. To differentiate between wheel bearings and

rear axle, drive the vehicle on a smooth road at

medium-low speed. With traffic permitting, turn
Fig.
74—Scored Hypoid Ring Gear

the vehicle sharply right and left. If noise is caused

by wheel bearings, it will increase in the turns be-

cause of the side loading. If noise cannot be isolated

to front or rear wheel bearings, inspection will be

necessary.

3.
Side bearings will produce a constant rough noise of

a slower nature than pinion bearings. Side bearing

noise will not fluctuate in the above wheel bearing

test.

Failure Analysis

The most common types of rear axle failures are

hypoid gear tooth scoring and fracture, differential gear

fracture. and/or differential bearing failure, and axle

shaft bearing failure.

Fig.
75-Cracked Hypoid Ring Gear

CHEVROLET CHASSIS SERVICE MANUAL

REAR SUSPENSION AND DRIVE LINE 4-30

Fig.
76—Differential Gear Failure

Hypoid Gears

Hypoid gear tooth scoring (fig. 74) is caused generally

by improper break-in, incorrect lube, insufficient gear

backlash or improper 'ring/pinion gear alignment. The

scoring will progressively lead to complete erosion of

the gear tooth, or gear tooth pitting and eventual fracture

with possible attendant damage to bearings, if the initial
scoring condition is not diagnosed in time and corrected.

Hypoid gear scoring is easily recognized by its char-

acteristic loud whine in either drive, coast or under both

conditions. Another cause of hypoid tooth fracture (fig.

75) is extended overloading of the gear set which will

produce fatigue fracture, or shock loading which will

result in sudden failure.

Differential Gears

Common causes of differential gear failure are shock

loading, extended overloading leading to fatigue failure,

and overheating of gear thrust surfaces resulting from

excessive wheel spin and consequent lubrication break-

down. Overheating will lead to seizing of thrust surfaces

or tooth failure (fig. 76).

Bearings

• Failure of axle tapered roller bearings is due pri-

marily to excessive wear caused by long service or

foreign materials in the oil. The second most common

cause of bearing failure is too tight or too loose pre-

load adjustment leading to spalling and eventual failure.

This failure may also lead to hypoid gear scoring due to

the resultant misalignment of the hypoid gear set.

COMPONENT PARTS REPLACEMENT

(Chevrolet, Cheveile, Chevy II and Camaro)

AXLE ASSEMBLY

Removal

1.
Raise vehicle to a height that will permit axle as-

sembly to hang freely and position supports under

both frame side rails.

2.
Disconnect wheel cylinder inlet lines. Disconnect and

remove brake hose and brake line retaining bracket

by removing retaining bolt from carrier cover.

3.
Loosen parking brake equalizer adjusting nut and

disconnect both rear cables at frame bracket and at

control arms. See Section 5 for detail of parking

brake cable removal.

4.
Remove two trunnion bearing "U" bolts from the

rear yoke and separate rear universal joint. Wire

propeller shaft to frame side rail and tape trunnion

bearing cups.

5. Support arid secure axle assembly with an adjustable

lifting device. On Chevrolet and Cheveile models,

loosen upper and lower control arm attaching bolts

at axle housing. (On Chevrolet models, disconnect

tie rod at axle bracket.)

6. Disconnect shock absorbers at axle brackets. Refer

to Shock Absorber Removal procedures outlined in

this section.

7. On Chevrolet and Cheveile models, lower axle as-

sembly until suspension reaches end of travel, then

disconnect spring retainers and withdraw springs

from vehicle.

8. On Chevy II and Camaro models, remove four nuts

securing lower spring seat to axle housing, then

remove spring front eye bolts or spring attaching

bracket and swing spring to rear so that it does not

interfere with axle.

9. On Chevrolet and Cheveile models, disconnect upper

and lower control arm attaching bolts at axle housing*
10.
Lower axle assembly and remove from under vehicle.

Installation

1.
Place axle assembly under vehicle and raise into

position.

2.
On Chevrolet and Cheveile models, install, but do not

tighten, upper and lower control arm attaching bolts

at axle housing.

3.
On Chevrolet models, position coil springs in upper

seats so that end of spring is indexed in seat.

4.
On Chevrolet models, install lower end of spring on

axle bracket or control arm and secure by installing

retainer and bolt. Install lock washer and retainer

nut.

5. On Cheveile pry lower pigtail of spring over vertical

flange of the axle bracket spring seat.

6. On Chevy II and Camaro models, install spring seat

pads and swing springs up into spring seats on axle

housing, making sure upper seat pads are aligned in

axle housing bracket.

7. Install spring front eye bolt and tighten, then install

spring seat lower mounting bracket and retaining

nuts.

8. Raise axle assembly to allow shock absorber and tie

rod installation. Position shock absorber in axle

bracket. Torque nut as outlined in Shock Absorber

Installation procedures.

9. Install brake hose and brake line retaining bracket

to carrier and connect wheel cylinder inlet lines.

Connect parking brake cable to frame bracket and

at control arm. Adjust parking brake and bleed

brakes as outlined in Section 5.

10.
Reassemble rear universal joint to companion flange.

11.
Support vehicle at axle and remove supports from

beneath the frame side rails.

12.
Remove supports and lower vehicle to floor. Torque

all affected parts to specifications.

CHEVROLET CHASSIS SERVICE MANUAL

REAR SUSPENSION AND DRIVE LINE 4-31

Fig.
77—Differential Pinion Shaft Removal

AXLE SHAFT

Removal

1.
Raise vehicle to desired working height and remove

wheel and tire assembly and brake drum.

2.
Clean all dirt from area of carrier cover. *

3.
Drain lubricant from carrier by removing cover.

4.
Remove the differential pinion shaft lock screw and

the differential pinion shaft (fig. 77).

5. Push flanged end of axle shaft toward center of

vehicle and remove "C" lock from button end of

shaft.

6. Remove axle shaft from housing, being careful not

to damage oil seal.

Wheel Bolt Replacement .

Press bolts out of axle shaft flange (as illustrated in

Figure 78) and press new bolts into place, making sure

that they are tight and square with flange.

Off Seal and/or Bearing Replacement

•1.
Remove the oil seal by using the button end of the

axle shaft - insert the button end of the shaft behind

the steel case of the oil seal, then pry seal out of

bore being careful not to damage housing.

2.
Insert Tool J-8119 into bore and position it behind

bearing so that tangs on tool engage bearing outer

x race. Remove bearing, using slide hammer as shown

in Figure 79. Figure 80 shows a detail of axle

housing outer end.

3.
Lubricate new bearing with wheel bearing lubricant,

and install bearing so that it bottoms against
Fig.
79—Wheel Bearing Removal

shoulder (fig. 81). To install bearing use Tool

J-21491 for the Chevelle, Camaro and Chevy JI

light-duty axle and Tool J-21051 for all Chevrolet

models and also for Chevelle, Camaro and Chevy tl

models with heavy-duty axle.

Pack cavity between the seal lips with a high melting

point wheel bearing lubricant; position seal on tool

(Use J-21491 for the Chevelle, Camaro and Chevy II

light-duty axle and J-21051 for all Chevrolet models

and also for Chevelle, Camaro and Chevy II models

with heavy-duty axle) and position seal in axle

housing bore, tap seal into place so that it bottoms

against bearing (fig. 81).

Brake Flange Plate Replacement

1.
Remove "brake line at wheel cylinder inlet and dis-

assemble brake components from flange plate. Refer

to Section 5 for brake disassembly procedure.

2.
Remove 4 nuts securing flange plate to axle housing.

3.
Install new flange plate to axle housing and torque

nuts to specifications.

Fig.
78—Wheel Bolt Replacement
Fig.
80-Axle Housing Detail

CHEVROLET CHASSIS SERVICE MANUAL

REAR SUSPENSION AND DRIVE LINE 4-32

HP?

Fig.
81
—Whed Bearing and/or Oil Seal Installation

4.
Install brake components on flange and connect

hydraulic line to wheel cylinder inlet. See Section 5

for brake assembly procedure.

5. Install axle shaft, brake drum and wheel and tire

assembly.

6. Bleed and. adjust brakes as outlined in Section 5.

Installation

1.
Slide axle shaft into place.

CAUTION: Exercise care that splines on end

of shaft do not damage oil seal and that they

engage with splines of differential side gear/

2.
Install axle shaft "C" lock on button end of axle-

shaft and push shaft outward so that shaft lock seats

in counterbore of differential side gear.

3.
Position differential pinion shaft through case and

pinions, aligning hole in shaft with lock screw hole.

Install lock screw and torque to specifications.

4.
Using a new gasket, install carrier cover and torque

bolts to specifications.

CAUTION: Make sure both gasket surfaces on

carrier and cover are clean before installing

new gasket. Torque carrier cover bolts in a

crosswise pattern to ensure uniform draw on

cover gasket.

5. Fill axle with lubricant to a level even with bottom

of filler hole. See Section 0 for proper lubricant.

6. Install brake drum and wheel and tire assembly.

7. Lower vehicle and test operation of axle.

PINION FLANGE, DUST DEFLECTOR

AND/OR OIL SEAL

Replacement

1.
Raise rear of vehicle and place stand jacks under

frame side rails so that axle hangs freely to allow

sufficient working room.

2.
Check wheels for freedom of rotation.

3.
Separate rear universal joint, tape trunnion bearings

to joint, position propeller shaft to one side and tie

it to frame side rail.

4.
Using Tool J-5853 with Adapter J-5810 and a suitable

socket on the pinion flange nut, rotate the pinion

through several complete revolutions and record the

torque required to keep the pinion turning (fig. 82).

If flange is to be reused, mark pinion and flange for

reassembly in the same relative position.

5. Install Tool J-8614-1 on pinion flange and remove

pinion flange nut and washer (fig. 83). (Position
Fig. 82—Measuring Drive Pinion Bearing Preload

J-8614-1 on flange so that the four notches are

toward flange.) Discard nut and use a new one

upon reassembly.

6. Thread pilot end of Tool J-8614-3 into small O.D.

end of J-8614-2. Then with J-8614-1 installed as

in Step 4, insert J-8614-2 into J-8614-1 and turn

it 45 degrees to locked position. Remove flange by

turning J-8614-3 while holding J-8614-1 (fig. 84).

7. Pry old seal out of bore, using a screw driver or a

hammer and chisel.

8. Inspect pinion flange for smooth oil seal surface,

worn drive splines, damaged ears, and for smooth-

ness of bearing contact surface. Replace if

necessary.

9. If deflector requires replacement, remove by tapping

from flange, clean up stake points; install new de-

flector, and stake deflector at three new equally

spaced positions.

NOTE:
Staking operation must be performed

in such a manner that the seal operating surface

is not damaged.

1.0. Pack the cavity between the seal lips of the pinion

flange oil seal with a lithium-base extreme pressure

lubricant, position seal in bore, then using Tools

J-21468 and J-9458, for light-duty axle and Tool

Fig. 83-—Drive Pinion Nut Removal

CHEVROLET CHASSIS SERVICE MANUAL

REAR SUSPENSION AND DRIVE LINE 4-36

Fig.
94—Installing Pinion Oil Seal

DIFFERENTIAL CARRIER

Removal

1.
Disconnect spring end link bolts as outlined in

Spring—Removal, in this section.

2.
Disconnect axle drive shafts at carrier by removing

"U"
bolts securing trunnion to side gear yoke.

3.
Disconnect carrier front support bracket at frame

crossmember.

4.
Disconnect propeller shaft at transmission and at

companion flange. Slide transmission yoke forward

into transmission. Drop propeller shaft down and
Fig.
95-Pinion Sea! Installed

out toward the rear.

5. Mark camber cam and bolt relative location on strut

rod bracket and loosen cam bolts.

6. Remove four bolts securing bracket to carrier lower

surface and drop bracket. Remove camber cam bolts

and swing strut rods up and out of the way.

7. Remove eight carrier-to-cover bolts. Loosen bolts

gradually to allow lubricant to drain out.

8. With mounting bolts removed, pull carrier partially

out of cover, drop nose to clear crossmember and

gradually work carrier down and out.

Installation

1.
Clean inside of carrier cover and liberally grease

gasket surface. Place new gasket on cover.

2.
Cut heads off two l/2"-13 x 1-1/4" bolts and slot

unthreaded end. Install these aligning studs into two

below-center carrier bolt holes, one on each side.

3.
Raise carrier into position aligning studs into

cover (fig. 96).

4.
Install carrier-to-cover bolts and tighten securely.

5. Connect propeller shaft to companion flange and

transmission yoke.

6. Install rubber cushion on bracket and position to

frame crossmember. Install hut and torque to

specifications.

7. Raise axle drive shafts into position and assemble

inboard trunnion to side gear yokes with "U" bolts.

8. Assemble strut rods to bracket and raise bracket

into position under carrier. Install four bolts and

torque to specifications. Move camber cams to

marked location and tighten cam nuts.

Fig.
96—Installing Carrier Assembly

CHEVROLET CHASSIS SERVICE MANUAL

REAR SUSPENSION AND DRIVE LINE 4-37

9. Connect spring end link bolts as outlined under

Spring--Installation, in this section.

10.
Remove filler plug, located on right side of cover,

and fill -with hypoid lubricant to level of filler hole.

11.
Lower vehicle and road test for leaks, noise and

general performance.

POSITRACTION DIFFERENTIAL UNIT

The optionally available Positraction differential unit

is installed in the conventional carrier to replace the

standard differential unit.

Service procedures for the Positraction equipped axle

are the same as on a conventional axle except for the.

operations listed below.

On the Vehicle Check

If vehicle is equipped with a manual transmission, shift

transmission into neutral.

1.
Raise rear of vehicle until wheels are off the ground,

remove one wheel and tire assembly.

2.
Attach Adapter J-5748 to axle shaft flange and install

a
1/2-13
bolt into adapter (fig. 97).

3.
With wheel and tire assembly still on vehicle held

firmly to prevent turning, measure torque required
Fig.
97—Measuring Positraction Rotating Torque

to rotate opposite axle shaft with a 0-150# torque

wrench attached to J-5748. Torque should be 70

ft.
lbs. minimum new, and no less than 40 ft. lbs. if

used.

PROPELLER SHAFT AND UNIVERSAL JOINTS

INDEX

Page
Page

General Description 4-37

Component Parts Replacement. 4-38

Propeller Shaft (Dana) 4-38

Removal 4-38

Repairs 4-38
Installation 4-39

Propeller Shaft (Saginaw) 4-40

Removal 4-40

Repairs 4-40

Installation 4-41

GENERAL DESCRIPTION

The one-piece, exposed-type, tubular propeller shaft is

used on all models. The cardon-type universal joints are

of the extended-life design and do not require periodic

maintenance. A splined front yoke on the front end of the

propeller shaft extends into a splined coupling on the

transmission output shaft. This slip joint permits slight

lengthening and shortening of the propeller shaft to com-

pensate for up and down movement of the rear axle
assembly.

A light duty (fig. 98) and a heavy duty (fig. 99) version

of the tubular propeller shaft is used. The heavy-duty

shaft incorporates a damper, as part of the sleeve yoke,

at the transmission end of the shaft. This damper is not

serviced separately—the sleeve and damper (fig. 100)

must be replaced as an assembly.

Two different methods are used to retain the trunnions

Fig.
98—Light-Duty Propeller Shaft Cross-Section (Dana Design)

CHEVROLET CHASSIS SERVICE MANUAL

REAR SUSPENSION AND DRIVE LINE 4-40

Fig.
106—Removing Propeller Shaft from Companion Flange

PROPELLER SHAFT (SAGINAW)

Removal

1.
Raise vehicle sufficiently to permit access to propel-

ler shaft and mark relationship of rear yoke to

companion flange.

2.
Remove trunnion bearing retaining strap attaching

screws from both bearings (fig. 106).

3.
Lower rear of propeller shaft, being careful not to

dislodge bearing caps from trunnion, and tape bear-

ing caps to trunnion.

4.
Withdraw propeller shaft front yoke from transmis-

.sion by moving shaft rearward, passing it under the

axle housing. Watch for oil leakage from transmis-

sion output shaft housing.

Repairs

NOTE:
Because of the elastic properties of the

nylon retainers, the trunnions must be pressed

from the yokes. Pressing the trunnions from the

yokes will shear the retainers which renders

the bearing caps unsuitable for reuse. A service

Jdt, which employs a snap ring to retain the

trunnion, must be used when reassembling the

propeller shaft (fig. 107).

1.
Remove trunnion at differential end of propeller shaft

Fig.
107—Service Kir Trunnion (Saginaw)
Fig.
108—Pressing Trunnion Bearing from Propeller Shaft

using the following procedure:

a. Support trunnion on a press bed so that the

propeller shaft yoke can be moved downward.

Support front of propeller shaft so that shaft is

in a horizontal position.

b.
Using a piece of pipe or similar tool, with an ins-

side diameter slightly larger than 1 1/8", press

bearing from yoke (fig. 108).

c. Apply force on yoke around bearing until nylon

retainer breaks. Continue to apply force until the

downward movement of the yoke forces the bear-

ing as far as possible from the yoke (fig. 109).

d. Complete removal of bearing by tapping around

circumference of exposed portion with a small

hammer (fig. 110).

e. Rotate propeller shaft so that opposite bearing

-may be removed in the manner described above.

f. Remove trunnion from yoke.

Remove trunnion at transmission end of propeller

shaft using the following procedure:

a. Support splined yoke on a press bed and the rear

of the propeller shaft on a stand so that shaft is

horizontal. Be sure that weight is evenly dis-

tributed on each side of the splined yoke and that

the fixed yoke half of the "U" joint is free to

move downward.

b.
Using a piece of pipe or similar tool, with an

inside diameter slightly larger than 1 1/8", press

bearing from yoke (fig. 108).

c. Apply force on yoke around bearing until nylon

retainer breaks. Continue to apply force until the

downward movement of the yoke forces the bear-

ing as far as possible from the yoke (fig. 109).

d. Complete removal of bearing by tapping around

circumference of exposed portion with a small

hammer (fig. 110).

e. Rotate propeller shaft so that opposite bearing

may be removed in the manner described above.

f. Remove splined yoke and trunnion from propeller

shaft.

CHEVROLET CHASSIS SERVICE MANUAL

REAR SUSPENSION AND DRIVE LINE 4-41

Fig.
109—Bearing Partially Pressed from Propeller Shaft

g. Support exposed trunnion fingers on press bed and

press splined yoke from bearing caps using

method described above,

h. Remove trunnion from splined yoke.

3.
Install trunnion and bearing assembly to the propel-

ler shaft yokes using the,following procedure:

NOTE:
The trunnion and bearing assembly used

at the differential end of the propeller shaft

incorporates two different size bearing caps.

The larger bearing caps (with the annular

grooves) must be mated with the propeller shaft

yoke.

a. Install bearing cap and seal about one-fourth way

in on one side of yoke, using a soft-faced hammer

to tap the bearing into position. Check bearing

cap during installation to ensure that it does not

become cocked in yoke.
Fig.
Ill—Installing Trunnion to Propeller Shaft

b.
Insert trunnion into yoke (fig. 111).

c. Firmly seat trunnion into bearing cup and press

bearing cup into yoke until it is flush with yoke.

d. Install opposite bearing cap and seal making sure

that rollers do not become jammed on trunnion.

Check for free movement of trunnion in yoke.

e. Install bearing retainer snap rings making sure

that gap in ring is toward yoke (fig. 112).

Installation

1.
Inspect yoke seal in the transmission extension, re-

place if necessary as described in the transmission

section.

2.
Insert propeller shaft front yoke into transmission

extension, making sure that output shaft splines

mate with propeller shaft yoke splines.

3.
Align propeller shaft with companion flange using

reference marks established in "Removal" pro-

cedure; remove tape used to retain trunnion bearing

caps;
connect exposed bearing caps to companion

flange by installing retaining strap and screws—

torque screws to specifications.

Fig.
110—Removing Bearing from Propeller Shaft
Fig.
112—Installing Snap Ring to Retain Trunnion

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 7-11

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