Table of Contents
Advertisement
2E-8
PROPELLER SHAFT
UNIVERSAL JOINT ANGLE MEASUREMENT AND
ADJUSTMENT
When torque is transmitted through single cardan
universal joints operating at an angle, the rotating
speeds of the driving and driven yoke will differ. In
operation, the driving yoke rotates at a constant speed
while the driven yoke speeds up and slows down twice
every revolution.
This difference in driven yoke rotating speed is pro
portional to the operating angle of the universal joint. In
effect, the greater the universal joint operating angle,
the greater the speed fluctuation of the driven yoke.
If fluctuation is excessive, driveline vibration will oc
cur. As a result, the universal joint operating angles
must be controlled to minimjze this effect.
On some Jeep models with Quadra-Trac, an incorrect
rear propeller shaft universal joint angle will generate
an audible-type vibration. The vibration occurs as a
constant booming or drone-like sound most noticeable in
the 40 to 60 mph (64 to 97 km/h) speed range.
If a vehicle exhibits this condition, the rear propeller
shaft universal joint and engine angles must be checked.
If the angles are not within specified limits, shims must
be installed between the rear axle spring pads and rear
spring to correct the angles. Shims are available in one,
two and three degree increments for this purpose. The
angle measurement and correction procedure is as
follows:
(1) Place vehicle on level surface.
(2) Measure engine downward angle as follows:
(a) Position protractor on left side of engine
block at transmission mounting ear. Place protractor in
fore and aft direction. Use mirror to view protractor if
necessary.
(b) Record engine downward angle, remove pro
tractor and proceed to next step.
(3) Measure pinion upward angle as follows:
(a) Place protractor on left side of rear axle
housing on flat machined surface of housing that is next
to welded plug. Be sure this surface is free of weld flash.
* (b) Record pinion upward angle, remove pro
tractor and proceed to next step.
(4) If pinion upward angle is one degree less than
engine downward angle, pinion angle is within specified
limits. Check for other causes of vibration.
(5) If pinion upward angle is greater than engine
downward angle by more than one degree, pinion angle
must be adjusted as follows.
EXAMPLE:
If the engine angle measures 5 degrees
downward and the pinion angle measures 7 degrees up
ward, the pinion angle must by adjusted downward 3
degrees. This changes the pinion downward angle to 4
degrees which is the required one degree less than the
engine downward angle.
(6) Adjust pinion angle as outlined in following
steps.
(7) Raise rear of vehicle and place support stands
under frame rails.
(8) Position hydraulic jack under axle housing and
raise jack just enough to support weight of axle.
(9) Remove rear wheels.
(10) Loosen rear spring U-bolt nuts.
(11) Install appropriate degree tapered shim between
spring and axle spring pad as follows:
(a) On vehicles with spring mounted aboveaxle,
if angle must be adjusted downward, install shim so
thickest end is facing front of vehicle. However, if angle
must be adjusted upward, install shim so thickest end is
facing rear of vehicle.
(b) On vehicles with spring mounted below axle,
if angle must be adjusted downward, install shims so
thickest end is facing rear of vehicle. However, if angle
must be adjusted upward, install shims so thickest end
is facing front of vehicle.
(12) Tighten U-bolt nuts to 100 foot-pounds (135
N«m) torque.
(13) Install rear wheels.
(14) Removesupport stands and lower vehicle.
LUBRICATION
The propeller shaft slip yoke and universal joints on
all Jeep vehicles require periodic lubrication. Refer to
the Maintenance Schedule in Chapter B for specific
details.
Lubricant Type
When lubricating the slip yokes and universal joints,
use Jeep Chassis Lubricant or an equivalent lithium-
base chassis grease only.
Lubrication Intervals
On Cherokee, Wagoneer and Truck models, the slip
yokes and universal joints must be lubricated at 12,500
mile (20 000 km) or 12.5 month intervals in normal serv
ice and at 5,000 mile (8 000 km) or 5 month intervals for
heavy-duty service.
On CJ and Scrambler models, the slip yoke and uni
versal joints must be lubricated at 5,000 mile (8 000km)
or 5 month intervals in normal service and at 2,500 mile
(4 000 km) or 2.5 month intervals for heavy-duty service.
Lubrication Fittings
Externally mounted lubrication fittings are located in
the slip yokes and single cardan universal joint spiders
for lubrication purposes.
Double cardan universal joints have special ball and
springfittings that require a needle-type lubegun nozzle
adapter (fig. 2E-7). When lubricating double cardan
joints, use Lube Fitting Adapter J-25512-2 (fig. 2E-8) or
Alemite Lube Fitting Adapter 6783, or equivalent.
Advertisement
Table of Contents
Troubleshooting
