Diagnosis Of The Propeller Shaft And Universal Joint - GMC G Service Manual

4A-4 PROPELLER SHAFT
DIAGNOSIS OF THE PROPELLER SHAFT AND
PROBLEM
Leak At The Front
Slip Yoke (An
Occasional Drop Of
Lubricant Leaking
From The Splined
Yoke Is Normal And
Requires No
Attention)
Universal Joint Noise
Ping, Snap, Or Click
In Drive Line (Usually
Heard On Initial Load
After The
Transmission Is In
Gear; Forward Or
Reverse)
Knocking Or
Clunking Noise In
The Driveline When
Operating The Vehicle
In A Floating
Condition In High Or
Neutral Gear At 10
MPH (16 km/h)
Roughness Or
Vibration
10. Distorted or damaged yokes or flanges.
11. Yokes out of phase.
12. Propeller shaft runout at 50 mph (80 km/h).
Scraping Noise
Roughness Above 35
MPH (56 km/h) Felt
And/Or Heard
UNIVERSAL JOINT
POSSIBLE CAUSE
1. Rough surface on splined yoke; burred,
nicked or worn.
2. Defective transmission rear oil seal.
1. Center bearing.
2. Worn universal joint bearings.
3. Improper lubrication.
4. Loose flange bolts.
1. Loose bushing bolts on the rear springs or
upper and lower control arms.
2. Loose or out of phase companion flange.
1. Worn or damaged universal joint.
2. Side gear hub counterbore in the differential
is worn oversize.
1. Bent or dented propeller shaft.
2. Undercoating on propeller shaft.
3. Tire unbalance, 30-80 mph (48-129 km/h).
Not throttle conscious.
4. Tight universal joints.
5. Worn universal joints.
6. Burrs or gouges on companion flange.
Check snap ring locating surfaces on flange
yoke.
7. Propeller shaft, parking brake drum or com­
panion flange is unbalanced.
8. Incorrect rear joint angle. The angle is usu­
ally too large when it is a factor.
9. Excessive looseness at the slip spline.
Throttle conscious.
Slinger, companion flange, or end yoke rub­
bing on rear axle or center bearing.
Tires unbalanced or worn.
CORRECTION
1. Replace the seal. Minor burrs can be
smoothed by careful use of crocus cloth or
fine stone honing. Replace the yoke if badly
burred.
2. Replace the transmission rear oil seal and
replenish the transmission oil.
1. Replace the center bearing.
2. Replace.
3. Lubricate as directed.
4. Tighten to "Specifications" later in this
section.
1. Tighten the bolts to specified torque.
2. Remove companion flange, turn 180 de­
grees from its original position, lubricate the
splines and install. Tighten the bolts and pin­
ion nut to specified torque.
1. Replace the worn or damaged universal
joint.
2. Replace the differential case and/or the
sidegears.
1. Replace propeller shaft.
2. Clean propeller shaft.
3. Balance or replace as required.
4. Impact yokes with a shaft hammer to free up.
If unable to free up or if joint feels rough when
rotated, replace.
5. Replace.
6. Rework or replace the companion flange.
7. Check for a missing balance weight on the
propeller shaft. Rotate the companion flange
180 degrees.
8. Check and correct trim height at curb weight.
Check and correct joint angle.
9. Replace necessary parts.
10. Install new yokes or flanges.
11. Remove companion flange, turn 180 de­
grees from the original position, lubricate the
splines and install. Tighten bolts to specified
torque.
12. Check propeller shaft runout at front and
rear. Should be less than specified. If above,
rotate propeller shaft 180 degrees and re­
check. Replace the propeller shaft if runout is
still over specification.
Correct the interference.
Balance or replace as required.
GMTB-0836-2L