Chevrolet Light Duty Truck 1973 Service Manual page 238

4 - 1 4 REAR SU SPEN SION AND DRIVELINE
PROPELLER SHAFT A N D UNIVERSAL JO IN T D IA G N O S IS
Checking and Correcting
Propeller Shaft Unbalance—Vehicles with
8-7/8" Ring Gear Differentials Only
1. Place vehicle on a twin post hoist so that the rear
wheels are free to rotate.
2. Remove both rear tire and wheel assemblies and
brake drums.
CAUTION:
Use care not t o apply brakes with
drums removed.
3. With vehicle running in gear at the indicated speed
where disturbance is at its peak, observe the
intensity of the disturbance.
COMPLAINT
Leak at front slip yoke.
NOTE: An occasional drop of
lubricant leaking from splined
yoke is normal and requires no
attention.
Knock in drive line, clunking
noise when car is operated
under floating condition at
mph in high gear or
10
neutral.
Ping, Snap or Click in drive
line.
NOTE: Usually occurs on
initial load application after
transmission has been put
into gear, either forward or
reverse.
4. Stop engine and check for any mud or undercoat­
5. Bring indicated speed up to the point where
. Install rear drums and wheels, and road test vehicle
6
DIAGNOSTIC CHART
POSSIBLE CAUSE
a. Rough outside surface on splined
yoke.
b. Defective transmission rear oil
seal.
a. Worn or damaged universal
joints.
b. Size gear hub counterbore in
differential worn oversize.
a. Loose upper or lower control
arm bushing bolts.
b. Loose companion flange.
Fig. 33A—Diagnosis Chart A
ing on the propeller shaft. If any is found, remove
it and again check the intensity of the vibration. If
vibration is still present, proceed to step 5.
disturbance was at its peak on the road test and
observe the intensity of the disturbance. Stop
engine and disconnect drive shaft from companion
flange. Reinstall shaft by rotating it 180° from its
original position. Determine which position of the
companion flange gives the best balance.
for final check of balance. If balance is still
unacceptable, replace drive shaft.
CORRECTION
a. Replace seal if cut by burrs on yoke.
Minor burrs can be smoothed by careful
use of crocus cloth or honing with a
fine stone. Replace yoke if outside
surface is rough or burred badly.
b. Replace transmission rear oil seal.
c. Bring transmission oil up to proper
level after correction.
a. Disassemble universal joints, inspect
and replace worn or damaged parts.
b. Replace differential case and/or side
gears as required.
a. Tighten bolts to specified torque.
b. Remove companion flange, turn 180°
from its original position, apply white
lead to splines and reinstall. Tighten
pinion nut to specified torque.
LIGHT DUTY TRUCK SERVICE MANUAL