93ZJ-Secc-16-Propeller-Shafts.pdf

PROPELLER SHAFTS

16 - 1

PROPELLER SHAFTS

CONTENTS

page

GENERAL INFORMATION .................. 1

PROPELLER SHAFT REPLACEMENT ......... 7

SERVICE DIAGNOSIS/PROCEDURES ......... 3

TORQUE SPECIFICATIONS ................ 14

UNIVERSAL JOINT REPLACEMENT .......... 9

GENERAL INFORMATION

PROPELLER SHAFTS

The function of a prop shaft is to transmit power

from one point to another in a smooth action. The

shaft is designed to send torque through an angle

from the transmission (transfer case on 4WD ve-

hicles) to the axle (Fig. 1).

The propeller shaft must operate through con-

stantly changing relative angles between the trans-

mission and axle. It must also be capable of changing

length while transmitting torque. The axle rides sus-

pended by springs in a floating motion. This means

the propeller shaft must be able to change angles

when going over various roads. This is accomplished

through universal joints, which permit the propeller

shaft to operate at different angles. The slip joints (or

yokes) permit contraction or expansion.

Tubular propeller shafts are balanced by the manu-

facturer with weights spot welded to the tube.

The propeller shaft is designed and built with the

yoke lugs in line with each other which is called

phasing. This design produces the smoothest running

condition. An out of phase shaft can cause a vibration.

Before undercoating a vehicle, the propeller

shaft and the U-joints should be covered. This

will prevent the undercoating from causing an

unbalanced condition and vibration.

CAUTION: Use exact replacement hardware for at-

taching the propeller shafts. This will ensure safe

operation. The specified torque must always be ap-

plied when tightening the fasteners.

UNIVERSAL JOINTS

The front and rear prop shafts use the 1310 series

universal joint.

Two different types of U-joints systems are used:

Single cardan U-joint (Fig. 2)

Double cardan U-joint (Fig. 3)

LUBRICATION

The slip yoke on the front shaft is equipped with a

zerk type lubrication fitting. Use a multi-purpose

NLGI Grade 2 EP lubricant, refer to Group 0, Lubri-

cation and Maintenance for additional information.

The factory installed U-joints are lubricated for the

Fig. 1 Front & Rear Propeller Shafts (4WD)

16 - 2 PROPELLER SHAFTS

life of the vehicle and do not need re-lubrication. All

U-joints should be inspected for leakage and damage

each time the vehicle is serviced. If seal leakage or

damage exists, the U-joint should be replaced.

Fig. 2 Single Cardan U-Joint (Typical)

Fig. 3 Double Cardan (CV) U-Joint

PROPELLER SHAFTS

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SERVICE DIAGNOSIS/PROCEDURES

INDEX

page

Runout ................................ . 4

Unbalance .............................. . 3

Universal Joint Angle Measurement ............ 4

Vibration ............................... . 3

VIBRATION

Tires that are out-of-round or wheels that are unbalanced

will cause a low frequency vibration. Refer to Group 22,

Tires And Wheels for additional information.

Brake drums that are unbalanced will cause a

harsh, low frequency vibration. Refer to Group 5,

Brakes for additional information.

Driveline vibration can also result from loose or

damaged engine mounts. Refer to Group 21, Trans-

missions for additional information.

Propeller shaft vibration will increase as the vehicle

speed is increased. A vibration that occurs within a

specific speed range is not caused by propeller shaft

unbalance. Defective universal joints or an incorrect

propeller shaft angle are usually the cause.

Inspect the propeller shaft for missing balance

weights, broken welds, and bent areas. If the propel-

ler shaft is bent, it must be replaced.

Ensure the universal joints are not worn, are properly

installed, and are correctly aligned with the shaft.

Check the universal joint clamp screws torque.

(1) Raise the vehicle.

(2) Remove the wheel and tires. Install the wheel

lug nuts to retain the brake drums.

(3) Mark and number the prop shaft tube six

inches from the yoke end at four positions 90° apart.

(4) Run and accelerate the vehicle until vibration

occurs. Note the intensity and speed the vibration

occurred. Stop the engine.

(5) Install a screw clamp at Position 1 (Fig. 1).

(6) Start the engine and re-check for vibration. If

there is little or no change in vibration, move the

clamp to one of the other three positions. Repeat the

vibration test.

(7) If there is no change in vibration, the vibration

may not be caused by prop shaft unbalance.

(8) If the vibration decreased, install a second

clamp (Fig. 2). Repeat the vibration test.

(9) If the clamps cause an additional unbalanced

DRIVELINE VIBRATION

UNBALANCE

If propeller shaft unbalance is suspected, it can be

verified with the following procedure.

Removing and re-indexing the propeller shaft

180° may eliminate some vibrations.

Clean all the foreign material from the propeller shaft

and the universal joints (mud, undercoating, etc.).

16 - 4 PROPELLER SHAFTS

(11) Install the wheel and tires. Lower the vehicle.

(12) If the amount of vibration remains unaccept-

able, apply procedures at the front end of the propel-

ler shaft.

Fig. 1 Clamp Screw At Position 1

RUNOUT

(1) Remove dirt, rust, paint, and undercoating from

the propeller shaft surface. Areas where the dial indi-

cator will contact the shaft must be clean.

(2) The dial indicator must be installed perpendicu-

lar to the shaft surface.

(3) Measure runout at the center and ends away

from welds.

(4) Refer to Runout Specifications chart.

(5) Replace the propeller shaft if the runout ex-

ceeds the limit.

RUNOUT SPECIFICATIONS

UNIVERSAL JOINT ANGLE MEASUREMENT

Fig. 2 Two Clamp Screws At The Same Position

INFORMATION

When two shafts intersect at a common universal

joint, the angle is called the operating angle. The

larger the operating angle, the larger the amount of

acceleration and deceleration of the joint. For every

revolution there are two accelerations and decelera-

tion of the universal joint. This speeding up and

slowing down of the joint must be cancelled to pro-

duce a smooth power flow. This is done through phas-

ing and proper universal joint working angles.

A propeller shaft is properly phased when the yoke

ends are on the same plane or in line. A twisted shaft

will throw the yokes out of phase and cause a notice-

able vibration.

When taking universal joint angle measurements or

checking phasing with two piece shafts, consider each

shaft separately. On 4WD vehicles, the front shaft

input (pinion shaft) angle has priority over the caster

angle.

Ideally the driveline system should have:

condition. Separate the clamp screws (1/4 inch above

and 1/4 inch below the mark). Repeat the vibration

test (Fig. 3).

Fig. 3 Clamp Screws Separated

(10) Increase distance between the clamp screws

and repeat the test until the amount of vibration is at

the lowest level. Bend the slack end of the clamps so

the screws will not loosen.

Angles that are equal or opposite within 1

degree of each other

Have a 3 degree maximum operating angle

PROPELLER SHAFTS

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Have at least a 1/2 degree continuous operat-

ing (propeller shaft) angle

Engine speed (R.P.M.) is the main factor in deter-

mining maximum allowable operating angles. As a

guide to maximum normal operating angles refer to

the chart listed (Fig. 4).

Fig. 4 Maximum Angles and R.P.M.

INSPECTION

Before measuring universal joint angles, the

following must be done.

Fig. 5 Front (Output) Angle Measurement (A)

Inflate all tires to correct pressure.

Check angles in the same loaded or unloaded

condition as when the vibration occurred. Prop

shaft angles will change according to the

amount of load in the vehicle. Always check

angles in loaded and unloaded conditions.

Check the condition of all suspension springs and

verify all fasteners are torqued to specifications.

Check the condition of the engine and transmission

mounts. Verify all fasteners are torqued to specifica-

tions.

MEASUREMENT

To accurately check driveline alignment, raise and

support the vehicle at the axles as level as possible.

Allow the wheels and propeller shaft to turn. Remove

snap rings from universal joint so Inclinometer 7663

(J-23498A) base sits flat on cap.

(1) Rotate the shaft until transmission/transfer

case output yoke bearing is facing downward.

Always make measurements from front to

rear.

(2) Place Inclinometer on yoke bearing (A) parallel

to the shaft (Fig. 5). Center bubble in sight glass and

record measurement.

This measurement will give you the transmission or

OUTPUT YOKE ANGLE (A).

(3) Rotate propeller shaft 90 degrees and place In-

clinometer on yoke bearing parallel to the shaft (Fig.

6). Center bubble in sight glass and record measure-

ment.

This measurement will give you the PROPELLER

SHAFT ANGLE (C).

(4) Subtract smaller figure from larger (C minus A)

to obtain transmission OUTPUT OPERATING

ANGLE.

Fig. 6 Propeller Shaft Angle Measurement (C)

(5) Rotate propeller shaft 90 degrees and place In-

clinometer on pinion yoke bearing parallel to the

shaft (Fig. 7). Center bubble in sight glass and record

measurement.

This measurement will give you the pinion shaft or

INPUT YOKE ANGLE (B).

(6) Subtract smaller figure from larger (C minus B)

to obtain axle INPUT OPERATING ANGLE.

Refer to rules given below and the example in (Fig.

8) for additional information.

Operating angles less than 3°

At least 1/2 of one degree continuous operating

(propeller shaft) angle

Good cancellation of u-joint operating angles

(within 1°)

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