The numbers below refer to the step numbers on the diagnostic table.
Step
| Action
| Yes
| No
|
Caution: Refer to Work Stall Test Caution in the Preface section. |
1
| Are you sent here from the Vibration Analysis - Engine/Accessory Isolation table?
| Go to
Step 2
| Go to
Vibration Analysis - Engine/Accessory Isolation
|
2
|
- Raise and support the vehicle. Refer to
Lifting and Jacking the Vehicle .
- Remove the flywheel/flexplate-to-torque converter bolts access cover (if equipped).
- Determine if clearance enough to separate the transmission torque converter from the engine flywheel/flexplate and secure the torque converter from accidentally engaging with the flywheel/flexplate.
Does the clearance enough to separate the transmission torque converter from engine flywheel/flexplate, and safely secure the torque converter from contacting with engine flywheel/flexplate?
| Go to
Step 3
| Go to
Step 9
|
3
|
- With the flywheel/flexplate to torque converter access cover removed and vehicle raised, and then mark the relative position between the transmission torque converter and engine flywheel/flexplate.
- Disconnect the torque converter and move it away from the flywheel/flexplate.
- Secure the transmission torque converter away from the engine flywheel/flexplate.
- Lower the vehicle, start the engine and allow the engine to idle.
- Raise and support the vehicle. Refer to
Lifting and Jacking the Vehicle .
- Visually inspect the flywheel/flexplate for excessive lateral runout.
- Lower the vehicle.
- Turn OFF the ignition.
Does the flywheel/flexplate have excessive lateral runout?
| Go to
Step 6
| Go to
Step 4
|
4
|
- Raise and support the vehicle. Refer to
Lifting and Jacking the Vehicle .
- Inspect the flywheel/flexplate for the following conditions:
• | Loose connection at the engine crankshaft |
• | Missing balance weights |
Does the flywheel/flexplate exhibit the above listed conditions ?
| Go to
Step 6
| Go to
Step 5
|
5
|
- With the transmission torque converter still secured away from the engine flywheel/flexplate to avoid accidental engagement with the flywheel/flexplate.
- Block the front wheels.
- Apply BOTH the service brake and park brake.
- With the scan tool and the
J 38792-A , Electronic Vibration Analyzer (EVA) 2, still installed, start the engine.
- Place the transmission in NEUTRAL or PARK.
- Slowly increase the engine (RPM) to the level at which the disturbance is most noticeable.
- Record the engine RPM obtained on the scan tool and the most dominant frequency reading if data is obtained from
J 38792-A .
- Turn OFF the ignition.
Does the disturbance significantly reduce or eliminate?
| Go to
Step 7
| Go to
Step 9
|
6
|
- If the flywheel/flexplate is loose at the engine crankshaft, tighten the flywheel/flexplate mounting bolts according to tightening specification and sequence.
- If the flywheel/flexplate is cracked, damaged, and/or has missing balance weights, replace the damaged flywheel/flexplate. Refer to following procedures:
Have you finished the tight or replacement operation?
| Go to
Step 12
| --
|
7
|
- Raise and support the vehicle. Refer to
Lifting and Jacking the Vehicle .
- Re-fit the transmission torque converter to the engine flywheel/flexplate, 120 degrees away from its original position.
- Reconnect the transmission torque converter to the engine flywheel/flexplate.
- Lower the vehicle.
- Block the front wheels.
- Apply BOTH the service brake and park brake.
- Start the engine, with the scan tool
J 38792-A still installed.
- Place the transmission in NEUTRAL or PARK.
- Slowly increase the engine (RPM) to the level at which the disturbance is most noticeable.
- Record the engine RPM obtained on the scan tool and the most dominant frequency reading if data is obtained from
J 38792-A .
- If the disturbance is still noticeable, re-position the torque converter to obtain the least amount of disturbance.
Does the disturbance significantly reduce or eliminate?
| Go to
Step 12
| Go to
Step 8
|
8
| Replace the out-of-balance transmission torque converter.
Have you finished the replacement?
| Go to
Step 12
| --
|
9
|
- Raise and support the vehicle. Refer to
Lifting and Jacking the Vehicle .
- Place the
J 38792-A sensor onto the underside of the oil pan along the FRONT edge.
- Lower the vehicle.
- Block the front wheels.
- Apply BOTH the service brakes and the park brake.
- Start the engine, with the scan tool and
J 38792-A still installed.
- Place the transmission in NEUTRAL or PARK.
- Slowly increase the engine (RPM) to the level at which the disturbance is most noticeable.
- Record the engine RPM obtained on the scan tool and the most dominant frequency reading (if obtained on the
J 38792-A from the underside of the engine oil pan).
- Repeat steps 1 to 9, place the
J 38792-A sensor onto the underside of the oil pan along the REAR edge.
Is the disturbance greatest when placing along the engine FRONT edge?
| Go to
Step 11
| Go to
Step 10
|
10
| Replace imbalanced engine flywheel/flexplate. Refer to the following procedures:
Have you finished the replacement?
| Go to
Step 12
| --
|
11
| Replace the engine crankshaft balancer. Refer to the following procedures:
Have you finished the replacement?
| Go to
Step 12
| --
|
12
|
- Install or connect all components that were removed or disconnected during diagnosis.
- Perform the Vibration - Road Testing table. Refer to
Vibration Analysis - Road Testing .
Is the disturbance still present?
| Go to
Vibration Diagnostic Aids
| System OK
|