Part 1 of 2

Diagnosis will be much easier once you have identified a vibration as first-order of driveline rotation during the road test. Next identify the exact area of the vibration and take proper action.

In most cases, vibration may be reproduced in the stall. In the stall the vibration may be better or worse than that experienced during the road test.
The objective is to reduce the vibration to the lowest point possible in the stall, then evaluate the results during a road test. Many times, a vibration you were only able to reduce drastically in the stall will be completely eliminated on the road.

The cause of first-order drive line vibration is usually excessive runout or an imbalanced component.
The following procedure offers a systematic process of elimination in order to determine which component is at fault:
1. Raise the vehicle to curb height. Support the vehicle on a hoist or heavy stands. Refer to Lifting and Jacking the Vehicle in General Information.
2. Remove the rear tire/wheel assemblies.
3. Remove and inspect the brake drums.
4. Inspect the propeller shaft. The propeller shaft should be free of undercoating before continuing.
5. Inspect the propeller shaft or U-Joint for any obvious dents or damage. Dents or damage will contribute to first-order driveline vibrations.
6. Start the engine.
7. Place the transmission in gear.
8. Run the vehicle up to the speed at which the vibration was most severe. Do not step on the brake while the brake drums are removed.
9. Record whether the vibration was present, and at what speed.
10. If the vibration is not present, complete a first-order driving vibration testing (Torque Sensitive).
11. If the vibration is present, determine which end of the drive shaft is vibrating the most. Hold your hand against the pinion nose and the transmission tailshaft, or hold an EVA vibration sensor up to each component.
12. If the vehicle is equipped with a two-piece propeller shaft, inspect the center support bearing for vibration.
13. If the transmission tail is vibrating, touch the transmission crossmember under the transmission mount. If there is no vibration on the crossmember, then the transmission mount is working properly.
14. Remember which end of the drive shaft is the worst, and how severe the vibration is. The inspection will be a reference by which to judge future progress.
Do not fill the propeller shaft with foam, oil, or any other substance in order to correct a vibration. Filling the propeller shaft is only effective in reducing an unrelated condition called Torsional Rattle. Filling the propeller shaft should only be done in strict adherence to the procedure outlined in corporate bulletins that address Torsional Rattle. Failure to follow the correct procedure will induce a vibration and/or affect the structural integrity of the propeller shaft. The propeller shaft will then have to be replaced.

Propeller Shaft Runout
A propeller shaft or pinion (companion) flange with excessive runout causes first-order driveline vibrations. Use the following procedure in order to measure the runout of the propeller shaft:
1. Remove excess corrosion of the propeller shaft surface before inspecting the runout.
2. Inspect for damage and dents.
3. Replace dented propeller shafts.
4. Remove any undercoating from the propeller shaft before proceeding.
5. Refer to Measuring Propeller Shaft Runout (below) for the measurement procedure that applies to the following shaft assemblies:
- One-piece
- Two-piece
The splined end of a propeller shaft is critical to the smooth operation of a two-piece propeller shaft. When inspecting stub-shaft runout, ensure that the dial indicator readings are accurate.
The front or the auxiliary propeller shaft on 4-wheel (4WD) drive models may sometimes cause vibration.
If a first-order vibration is present only when the vehicle is in 4WD, remove the auxiliary propeller shaft and re-evaluate the vibration. If the vibration disappears, the auxiliary shaft is most likely at fault.
Investigate the condition of the auxiliary shaft.

Measuring Propeller Shaft Runout
Tools Required
- J 8001 Dial Indicator Set
- J 7872 Magnetic Base Dial Indicator Set




1. Raise the vehicle on a suitable hoist. Refer to Lifting and Jacking the Vehicle in General Information.
2. Allow the wheels to spin freely.




3. Attach a J8001 and a J7872.
4. Place the transmission in NEUTRAL.
5. Rotate the pinion flange or the transmission yoke by hand while taking the measurements for the runout.

Important: The propeller shaft turns easier in one direction than in the other. Removing the wheels and the drums will also help. Do not include fluctuations on the dial indicator due to welds or surface irregularities.

6. Perform the following steps for one-piece propeller shafts if the runout exceeds the tolerances at one or more points:
1. Rotate the propeller shaft 180 ° in the pinion flange.
2. Reinstall the propeller shaft.
3. Inspect the measurement.
4. If the runout still exceeds the tolerance, inspect the pinion flange runout before replacing the propeller shaft.

7. Perform the following steps for 2-piece propeller shafts if the runout exceeds the tolerances at I or more points:

Important: The runout of the rear splines on the front propeller shaft affects the runout of the front measurement on the rear propeller shaft.

1. Measure the rear propeller shaft.
2. Mark the position of the rear shaft in the pinion flange.
3. Remove the rear shaft.
4. Measure the front propeller shaft runout on the tube and the stubshaft.
5. Replace the propeller shaft if either measurement is out of tolerance.

Important: When you replace a propeller shaft, inspect the new shaft for runout. Inspect the pinion flange runout if the replacement shaft runout is also out of tolerance.

Propeller Shaft Measurement Points: