The numbers below refer to the step numbers in the diagnostic table.
First-order driveline related vibrations are usually caused by components that exhibit excessive runout or imbalance. Reproducing a vibration concern in the service stall can aid in pin-pointing the component which may be at fault. (A vibration concern may appear to be either less severe or more severe when duplicated in a service stall, than when duplicated on the road.)
First-order driveline related vibrations that could not be duplicated during the non-torque sensitive service stall test, could be caused by internal axle components. This test is designed to duplicated first-order driveline related vibrations that are sensitive to torque/load. (A vibration concern may appear to be either less severe or more severe when duplicated in a service stall, than when duplicated on the road.)
First-order driveline vibrations can be caused by excessive runout of a propeller shaft.
First-order driveline vibrations can be caused by excessive runout of the pinion flange. If a propeller shaft exhibits excessive runout at a pinion flange end only, the runout may actually be caused by the pinion flange.
Re-indexing a propeller shaft to a pinion flange can reduce the amount of total combined runout which the components produce, which may in-turn reduce a vibration.
Step  | Action  | Yes  | No  | ||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
1  | Has the Vibration Analysis - Road Testing table been completed?  | Go to Step 2  | |||||||||||||
2  | Did you record frequency data from the J 38792-A during the Vibration Analysis - Road Testing procedure?  | Go to Step 3  | Go to Step 5  | ||||||||||||
3  | Based on the Vibration Analysis - Road Testing table, is the concern first order driveline related?  | Go to Step 6  | Go to Step 4  | ||||||||||||
4  | Based on the Vibration Analysis - Road Testing table, is the concern second order driveline related?  | Go to Step 19  | Go to Step 5  | ||||||||||||
5  | Based on the Vibration Analysis - Road Testing table, is the concern a noise that is not felt?  | ||||||||||||||
6  | Inspect the following components for wear or damage: 
 
 
 Are any of the components listed worn or damaged?  | Go to Step 7  | Go to Step 8  | ||||||||||||
7  | Replace the damaged or missing components. Refer to one of the following procedures in Propeller Shaft: 
 Did you complete the replacement?  | Go to Step 26  | --  | ||||||||||||
Attempt to duplicate the vibration in the stall. Refer to Vibration in Service-Stall Test (Non-Torque Sensitive) Were you able to duplicate the vibration?  | Go to Step 10  | Go to Step 9  | |||||||||||||
Perform the Vibration in Service-Stall Test (Torque Sensitive) . Were you able to duplicate the vibration?  | Go to Diagnostic Starting Point - Rear Drive Axle in Rear Drive Axle  | ||||||||||||||
10  | Was the vibration most evident under the transmission mount?  | Go to Step 11  | Go to Step 13  | ||||||||||||
Measure the runout at the rear of the front axle propeller shaft, if equipped and measure the runout at the front of the forward-most rear axle propeller shaft. Refer to Propeller Shaft Runout Measurement . Does the runout measurement require that the propeller shaft(s) be replaced?  | Go to Step 13  | Go to Step 12  | |||||||||||||
12  | 
 
 
 
 
 
 
 Is the vibration still present?  | Go to Step 13  | Go to Step 26  | ||||||||||||
13  | Measure the runout of the complete propeller shaft(s). Refer to Propeller Shaft Runout Measurement . Does the runout measurement require that the propeller shaft(s) be replaced?  | Go to Step 14  | Go to Step 15  | ||||||||||||
14  | 
 Was the vibration reduced or eliminated?  | Go to Step 26  | Go to Step 17  | ||||||||||||
Determine the runout of the front axle pinion flange, if equipped, and determine the runout of the rear axle pinion flange. Refer to the Pinion Flange Runout Measurement . Does the runout measurement require that the (front and/or rear) pinion flange be replaced?  | Go to Step 16  | Go to Step 17  | |||||||||||||
16  | Replace the pinion flange. Refer to Front Differential Drive Pinion Flange/Yoke, Seal, and Dust Deflector Replacement in Front Drive Axle and/or Drive Pinion Flange/Yoke and/or Oil Seal Replacement in Rear Drive Axle. Did you complete the replacement?  | Go to Step 26  | --  | ||||||||||||
Re-index the propeller shaft. Perform the following steps: 
 Was the vibration reduced or eliminated?  | Go to Step 26  | Go to Step 18  | |||||||||||||
18  | Return the propeller shaft to it's original position and balance the propeller shaft. Refer to Driveline System Balance Adjustment . Were you able to balance the driveline system?  | Go to Step 26  | |||||||||||||
19  | Inspect the following components for wear or damage: 
 
 
 Are any of the components listed worn or damaged?  | Go to Step 20  | Go to Step 21  | ||||||||||||
20  | Replace the damaged or missing components. Refer to one of the following procedures in Propeller Shaft: 
 Did you complete the replacement?  | Go to Step 26  | --  | ||||||||||||
21  | 
 Refer to Trim Height Inspection in Suspension General Diagnosis. Did you find and correct a condition?  | Go to Step 26  | Go to Step 22  | ||||||||||||
22  | Measure the propeller shaft angles. Refer to Driveline Working Angles Measurement . Do the propeller shaft angles require adjustment?  | Go to Step 23  | Go to Step 24  | ||||||||||||
23  | Adjust the propeller shaft angles. Refer to Driveline Working Angles Adjustment . Did you complete the repair?  | Go to Step 26  | --  | ||||||||||||
24  | Inspect the propeller shafts for proper phasing. Refer to Propeller Shaft Phasing Inspection . Does the propeller shaft phasing require correction?  | Go to Step 25  | |||||||||||||
25  | Correct the propeller shaft phasing. Refer to Propeller Shaft Phasing Correction . Did you complete the repair?  | Go to Step 26  | --  | ||||||||||||
26  | 
 Is the vibration still present?  | Go to Step 3  | System OK  |