On-Vehicle Service; Propeller Shaft Runout Check - GMC G Service Manual

DIAGNOSIS OF THE PROPELLER SHAFT AND
UNIVERSAL JOINT (CONTINUED)
PROBLEM
Squeak 1.
2.
Whine Or Whistle
Shudder On 1.
Acceleration, (Low
Speed) 2.
3.
PROPELLER SHAFT
BALANCE CHECK
H Remove or Disconnect
• Raise the vehicle on a twin post hoist so the wheels
can spin.
1. Wheel and tire assemblies.
2. Brake drums or rotors. Refer to HYDRAULIC FOUN­
DATION BRAKES (SEC. 5A2).
• DO NOT APPLY THE BRAKE WITH THE
DRUMS REMOVED.
| y | Inspect
Propeller shaft, universal joints and attachments for
mud, undercoating or loose fasteners.
Clean
Propeller shaft, universal joints and attachments.
H O Tighten
Any loose attachments or fasteners to "Specifica­
tions" at the end of this section.
I ? | Important
Run the vehicle in gear at the speed where the distur­
bance peaks; observe the in te n sity of the
disturbance.
Stop the engine.
3. Propeller shaft.
• Rotate the propeller shaft 180 degrees from the
original position.
H Install or Connect
1. Propeller shaft.
• Determine the position which gives the best
balance.
POSSIBLE CAUSE
Lack of lubricant.
Center bearing.
Center support bearing.
Loose or missing bolts at the center bearing
or flanges.
Incorrectly set front joint angle.
Worn universal joint.

ON-VEHICLE SERVICE

PROPELLER SHAFT 4A-5
CORRECTION
1. Lubricate joints and splines. Also check for
worn or brinelled parts.
2. Replace or lubricate.
Place the vehicle on a hoist with rear wheels
free to rotate and diagnose for source of
noise, replace.
1. Replace or tighten bolts to specified torque.
2. Shim under the transmission support mount
to change the front joint angle.
3. Replace.
2. Brake drums or rotors. Refer to HYDRAULIC FOUN­
DATION BRAKES (SEC. 5A2).
3. Wheel and tire assemblies.
• Determine the position which gives the best driveline
response by road testing the vehicle for a final check
of the propeller shaft balance.
• If the balance is unacceptable, replace the propeller
shaft.
PROPELLER SHAFT
RUNOUT CHECK
Noise or vibration at high speed could be caused by a
bent propeller shaft. The propeller shaft could have been
damaged by rough handling or a collision. Check for propel­
ler shaft straightness.
1. Raise the vehicle on a twin post hoist so the wheels
can spin.
2. Attach a dial indicator having a magnetic base to a
smooth place on the vehicle underbody.
m Important
• Do not attach the dial indicator base at a weld.
3. Take dial indicator readings at the propeller shaft
check points shown in figure 5. For runout specifica­
tions, refer to figure 6.
4. With the transmission in neutral, hand rotate the axle
pinion flange or the transmission yoke and take the
necessary dial indicator readings on the propeller
shaft. Record the readings.
• One-piece: Measure the runout at the points
shown in figure 5. If runout exceeds specifica­
tions, rotate the propeller shaft 180 degrees at
the pinion flange and install. Check the runout
again.
GMTB-0837-2L