GMC chevrolet camaro 2000 Service Manual page 68

General Information
The last method involves running the vehicle at a
) speed which the vibration is felt.
1. Carefully hold a piece of chalk up to the very end
of the propeller shaft. Barely touch the chalk to
the shaft.
2. Shut the engine OFF in order to stop the propeller
shaft from rotating. Do not step on the brake
pedal. Do not put the transmission in PARK.
3. Inspect the chalk mark.
0.0 1.0
2.0
) 182176
If you performed the above procedure correctly, the
chalk. mark will indicate the heavy spot on the
shaft. The heavy spot will deflect downward and touch
the chalk. If the chalk mark circles the entire shaft,
touch the chalk more gently to the shaft. Ensure that
the chalk touches only the heavy spot. Once the
heavy spot is located, place the hose clamp
180 degrees opposite to the chalk mark (1 ). Perform
the following steps:
1. Place the hose clamp at the light spot, .or at any
of the 4 points marked previously.
2. Test drive the vehicle at the speed at which the
vibration occurred. Record any changes in the
vibration.
3. Move the clamp to the other positions.
4. Test drive the vehicle each time you move the
clamp. Record any changes in vibration.
Remember which position gives the best balance.
., If the vibration did not change at all or if the
vibration becomes worse, then one clamp is either
too light or too heavy. Repeat the procedure
using the two clamps together (2).
• If the previous step did not correct the problem,
repeat the procedure using the two clamps
separated in order to reduce the spinning weight.
Vibration. Di~gnosis and. Correction 0-57
Continue the trial and error procedure using different
weights in different locations until you achieve the best
balance. If more that thre.e clamps aligned in the
same position are required, replace the propeller shaft.
If you are able to reduce the vibration in the stall,
but are unable to eliminate the vibration completely,
perform a road test on the vehicle. A slight vibration
noticeable in the stall may not be noticeable on
the road.
Driveline System Balance with Electronic
Vibration Analyzer (EVA)
In order to pinpoint the source, you must reproduce
the vibration in the service stall. Determine which
component is vibrating the most using the EV A.
Perform the following steps:
1. Support the vehicle on a suitable hoist or on
safety stands. Ensure that the rear of the rear
axle is at curb height. Do not allow the axle
to hang. Refer to Lifting and Jacking the Vehicle
in General· Information.
2. Remove the rear tire/wheel assemblies. Refer to
Tire and Wheel Removal and Installation in Tires
and Wheels.
3. Ensure that the propeller shaft is free of
undercoating. Inspect for dents or damage to the
propeller shaft or the U-joint.
4. Start the engine.
5. Place the transmission in gear.
6. Run the engine at the vehicle speed at which the
vibration is occurring.
Caution: Do not run the vehicle higher than
89 km/h (55 mph). Stay clear of the universal joints
and the balance weight area in order to avoid
personal injury. Do not run the vehicle on the hoist
for extended periods of time. Running the vehicle
on the hoist for extended periods of time may
cause the engine or the transmission to overheat.
Determine which end of the propeller shaft is
vibrating the most. Hold the EVA's sensor against the
pinion nose and the transmission tailshaft assembly.
The higher the amplitude reading, the greater the
vibration.
• If the vehicle has a two-piece propeller shaft,
inspect the center support bearing .
.. If the transmission tailshaft vibrates, inspect the
transmission crossmember under the transmission
mount. The vibration should not be present if
the mount is functioning correctly.