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Step
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Action
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Yes
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No
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Refer to
Work Stall Test Warning
.
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1
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Were you sent here from the Vibration Analysis - Engine/Accessory Isolation table?
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Go to
Step 2
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Go to
Vibration Analysis - Engine/Accessory Isolation
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2
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Is the
EL-38792-A
Electronic Vibration Analyzer (EVA) 2 , available?
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Go to
Step 3
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Go to
Vibration Diagnostic Aids
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3
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Is the vehicle equipped with a manual transmission?
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Go to
Step 11
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Go to
Step 4
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4
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2.
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Remove the flywheel/flexplate-to-torque converter bolts access cover, if equipped.
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3.
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Determine if sufficient clearance exists to separate the transmission torque converter away from the engine flywheel/flexplate and safely secure the torque converter from accidentally engaging with the flywheel/flexplate.
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Is there sufficient clearance to separate and safely secure the transmission torque converter away from the engine flywheel/flexplate?
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Go to
Step 5
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Go to
Step 11
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5
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1.
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With the flywheel/flexplate-to-torque converter access cover still removed, and with the vehicle still raised, mark the position of the transmission torque converter in relation to the engine flywheel/flexplate.
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2.
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Disconnect the torque converter and move it away from the flywheel/flexplate.
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3.
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Secure the transmission torque converter away from the engine flywheel/flexplate to avoid accidental engagement with the flywheel/flexplate.
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4.
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Lower the vehicle, start the engine and allow the engine to idle.
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6.
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Visually inspect the flywheel/flexplate for excessive lateral runout.
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8.
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Turn OFF the ignition.
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Did the flywheel/flexplate exhibit excessive lateral runout?
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Go to
Step 8
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Go to
Step 6
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6
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2.
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Inspect the flywheel/flexplate for the following:
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•
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Looseness at the engine crankshaft
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•
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Missing balance weights
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Did the flywheel/flexplate exhibit any of the conditions listed?
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Go to
Step 8
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Go to
Step 7
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7
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1.
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With the transmission torque converter still secured away from the engine flywheel/flexplate to avoid accidental engagement with the flywheel/flexplate, lower the vehicle.
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2.
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Block the front wheels.
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3.
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Apply BOTH the service brakes and the park brake.
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4.
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With the scan tool and the
EL-38792-A
Electronic Vibration Analyzer (EVA) 2 still installed, start the engine.
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5.
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Place the transmission in NEUTRAL or PARK.
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6.
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Slowly increase the engine RPM to the level at which the disturbance is most noticeable.
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7.
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Record the engine RPM obtained on the scan tool and the most dominant frequency reading if obtained on the
EL-38792-A
Electronic Vibration Analyzer (EVA) 2.
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8.
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Turn OFF the ignition.
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Has the disturbance been significantly reduced or eliminated?
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Go to
Step 9
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Go to
Step 11
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8
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1.
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If the flywheel/flexplate is loose at the engine crankshaft, tighten the flywheel/flexplate mounting bolts in sequence and to specification.
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2.
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If the flywheel/flexplate is cracked, damaged, and/or has missing balance weights, replace the damaged flywheel/flexplate.
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Did you complete the tightening or replacement?
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Go to
Step 20
|
-
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9
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2.
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Re-index the transmission torque converter to the engine flywheel/flexplate, 120 degrees from its original position.
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3.
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Reconnect the transmission torque converter to the engine flywheel/flexplate.
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5.
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Block the front wheels.
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6.
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Apply BOTH the service brakes and the park brake.
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7.
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With the scan tool and the
EL-38792-A
Electronic Vibration Analyzer (EVA) 2 still installed, start the engine.
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8.
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Place the transmission in NEUTRAL or PARK.
|
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9.
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Slowly increase the engine RPM to the level at which the disturbance is most noticeable.
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10.
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Record the engine RPM obtained on the scan tool and the most dominant frequency reading if obtained on the
EL-38792-A
Electronic Vibration Analyzer (EVA) 2.
|
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11.
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If the disturbance is still noticeable, re-index the torque converter again to obtain the least amount of disturbance.
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Has the disturbance been significantly reduced or eliminated?
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Go to
Step 20
|
Go to
Step 10
|
10
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Replace the out-of-balance transmission torque converter.
Did you complete the replacement?
|
Go to
Step 20
|
-
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11
|
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2.
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Position the
EL-38792-A
Electronic Vibration Analyzer (EVA) 2 sensor onto the underside of the engine oil pan, along the FRONT edge.
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4.
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Block the front wheels.
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5.
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Apply BOTH the service brakes and the park brake.
|
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6.
|
With the scan tool and the
EL-38792-A
Electronic Vibration Analyzer (EVA) 2 still installed, start the engine.
|
|
7.
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Place the transmission in NEUTRAL or PARK.
|
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8.
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Slowly increase the engine RPM to the level at which the disturbance is most noticeable.
|
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9.
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Record the engine RPM obtained on the scan tool and the most dominant frequency reading if obtained on the
EL-38792-A
Electronic Vibration Analyzer (EVA) 2 from the underside of the engine oil pan.
|
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10.
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Repeat steps 1 through 9, placing the
EL-38792-A
Electronic Vibration Analyzer (EVA) 2 sensor onto the underside of the engine oil pan, along the rear edge.
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Is the disturbance greater along the FRONT of the engine?
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Go to
Step 19
|
Go to
Step 12
|
12
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Is the vehicle equipped with an automatic transmission?
|
Go to
Step 18
|
Go to
Step 13
|
13
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2.
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Remove the flywheel inspection cover.
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3.
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Start the engine. Allow the engine to idle.
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4.
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Visually inspect the engine flywheel clutch surface for excessive lateral runout.
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Does the engine flywheel clutch surface exhibit excessive lateral runout?
|
Go to
Step 18
|
Go to
Step 14
|
14
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Inspect the clutch pressure plate to engine flywheel mounting for proper factory indexing.
Is the clutch pressure plate properly indexed to the engine flywheel?
|
Go to
Step 16
|
Go to
Step 15
|
15
|
|
1.
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Remove the clutch pressure plate and clutch driven plate from the engine flywheel.
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2.
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Inspect the engine flywheel for the following:
|
|
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•
|
Looseness at the engine crankshaft
|
|
|
•
|
Cracks, warpage and/or damage
|
|
|
•
|
Missing balance weights
|
|
3.
|
Inspect the clutch pressure plate and clutch driven plate for the following:
|
|
|
•
|
Loose and/or damaged clutch driven plate damper springs
|
|
|
•
|
Loose and/or damaged clutch pressure plate diaphragm springs
|
|
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•
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Cracks, warpage and/or damage
|
|
|
•
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Missing balance weights
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Do any of the above conditions exist?
|
Go to
Step 18
|
Go to
Step 17
|
16
|
|
1.
|
Remove the clutch pressure plate and clutch driven plate from the engine flywheel.
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2.
|
Inspect the engine flywheel for the following:
|
|
|
•
|
Looseness at the engine crankshaft
|
|
|
•
|
Cracks, warpage and/or damage
|
|
|
•
|
Missing balance weights
|
|
3.
|
Inspect the clutch pressure plate and clutch driven plate for the following:
|
|
|
•
|
Loose and/or damaged clutch driven plate damper springs
|
|
|
•
|
Loose and/or damaged clutch pressure plate diaphragm springs
|
|
|
•
|
Cracks, warpage and/or damage
|
|
|
•
|
Missing balance weights
|
Do any of the above conditions exist?
|
Go to
Step 18
|
Go to
Vibration Diagnostic Aids
|
17
|
Re-index the pressure plate to the engine flywheel.
Did you complete the re-indexing?
|
Go to
Step 20
|
-
|
18
|
Replace the engine flywheel/flexplate.
Did you complete the replacement?
|
Go to
Step 20
|
-
|
19
|
Replace the engine crankshaft balancer.
Did you complete the replacement?
|
Go to
Step 20
|
-
|
20
|
Check the vehicle to determine if the disturbance is now significantly reduced or eliminated. Perform the following steps:
|
1.
|
Install or connect components that were removed or disconnected during diagnosis.
|
|
2.
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Install a scan tool into the customer's vehicle.
|
|
3.
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Install
EL-38792-A
electronic vibration analyzer (EVA) 2, if available, in the customer's car. Place the sensor in exactly the same location as it was originally placed in the customer's vehicle.
|
|
4.
|
Block the front wheels.
|
|
5.
|
Apply BOTH the service brakes and the park brake.
|
|
7.
|
Place the transmission in NEUTRAL or PARK.
|
|
8.
|
Slowly increase the engine RPM to the level at which the disturbance was most noticeable.
|
|
9.
|
Record the engine RPM obtained on the scan tool and the most dominant frequency reading if obtained on the
EL-38792-A
Electronic Vibration Analyzer (EVA) 2, if available.
|
|
10.
|
Place the transmission in DRIVE.
|
|
11.
|
Slowly increase the engine RPM to the level at which the disturbance was most noticeable.
|
|
12.
|
Record the engine RPM obtained on the scan tool and the most dominant frequency reading if obtained on the
EL-38792-A
Electronic Vibration Analyzer (EVA) 2, if available.
|
|
13.
|
If the disturbance has been significantly reduced or eliminated, confirm the results by placing the transmission into REVERSE, then repeat steps 11 and 12. Reverse-loading of the powertrain may increase or change the characteristics of the vibration.
|
Has the disturbance been significantly reduced or eliminated?
|
Go to
Step 21
|
Go to
Vibration Diagnostic Aids
|
21
|
Perform the Vibration Analysis - Road Testing table. Refer to
Vibration Analysis - Road Testing
.
Is the disturbance still present?
|
Go to
Vibration Diagnostic Aids
|
System OK
|
