[ Pobierz całość w formacie PDF ]
Z
PROPELLER SHAFTS
16 - 1
PROPELLER SHAFTS
CONTENTS
page
page
GENERAL INFORMATION ..................
PROPELLER SHAFT REPLACEMENT .........
SERVICE DIAGNOSIS/PROCEDURES .........
TORQUE SPECIFICATIONS ................
UNIVERSAL JOINT REPLACEMENT ..........
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:
²
Single cardan U-joint (Fig. 2)
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
Z
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
Z
PROPELLER SHAFTS
16 - 3
SERVICE DIAGNOSIS/PROCEDURES
INDEX
page
page
Runout ................................
Unbalance ..............................
Universal Joint Angle Measurement ............
Vibration ...............................
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.
²
Ensure the universal joints are not worn, are properly
installed, and are correctly aligned with the shaft.
²
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.
²
²
Clean all the foreign material from the propeller shaft
and the universal joints (mud, undercoating, etc.).
 16 - 4 PROPELLER SHAFTS
Z
(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
²
Have a 3 degree maximum operating angle
²
 Z
PROPELLER SHAFTS
16 - 5
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.
²
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.
²
Check the condition of all suspension springs and
verify all fasteners are torqued to specifications.
²
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.
²
Operating angles less than 3°
At least 1/2 of one degree continuous operating
(propeller shaft) angle
²
²
Good cancellation of u-joint operating angles
(within 1°)
²
²
[ Pobierz całość w formacie PDF ]