Test Description
The numbers below refer to the step numbers on the diagnostic table.
- 4 . If sufficient clearance exists to separate the transmission torque converter from the engine flywheel/flexplate, then further tests can be used to isolate the transmission from the engine.
- 5 . An engine flywheel/flexplate that has excessive lateral runout, when combined with the mass of the transmission torque converter, can produce a disturbance.
- 6 . An engine flywheel/flexplate that is loose at the engine crankshaft or that is cracked or damaged, when combined with the mass of the transmission torque converter, can produce a disturbance.
- 7 . This step is designed to isolate the transmission from the engine to determine if the disturbance is related to the engine ONLY.
- 9 . Re-indexing the transmission torque converter to the engine flywheel/flexplate alters the balance relationship between the torque converter and the rear of the engine.
- 11 . Placing the J 38792-A sensor onto the underside of the engine oil pan along the FRONT and the REAR edge allows for a determination to be made, which will help to narrow down the cause of the disturbance.
- 13 . An engine flywheel that has excessive lateral runout, when combined with the extra mass of the clutch pressure plate and clutch driven plate, can produce a disturbance.
- 14 . The clutch pressure plate and the engine flywheel are marked for proper indexing of the heavy-spot of one to the light-spot of the other. Improper indexing of the pressure plate to the flywheel can produce a disturbance.
- 15 . An engine flywheel that is loose at the engine crankshaft or that is cracked, damaged and/or missing balance weights; and/or a clutch pressure plate and clutch driven plate that has loose springs, cracks, warpage, damage and/or missing balance weights - can produce a disturbance when their mass is combined.
- 16 . An engine flywheel that is loose at the engine crankshaft or that is cracked, damaged and/or missing balance weights; and/or a clutch pressure plate and clutch driven plate that has loose springs, cracks, warpage, damage and/or missing balance weights - can produce a disturbance when their mass is combined.
- 17 . Re-indexing the pressure plate to the engine flywheel alters the balance relationship between the pressure plate/flywheel assembly and the rear of the engine.
- 18 . An engine flywheel/flexplate that is damaged, misaligned, and/or imbalanced, can produce a disturbance.
- 19 . An engine crankshaft balancer that is damaged, misaligned, and/or imbalanced, can produce a disturbance.
DIAGNOSTIC CHART
| Step | Action | Yes | No |
|---|---|---|---|
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WARNING:
Refer to WORK STALL TEST CAUTION
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| 1 | Were you sent here from the Vibration Analysis - Engine/Accessory Isolation table? | Go to Step 2 | Go to VIBRATION ANALYSIS - ENGINE/ACCESSORY ISOLATION |
| 2 | Is the J 38792-A, Electronic Vibration Analyzer (EVA) 2, available? | Go to Step 3 | Go to VIBRATION DIAGNOSTIC AIDS |
| 3 | Is the vehicle equipped with a manual transmission? | Go to Step 11 | Go to Step 4 |
| 4 |
Is there sufficient clearance to separate and safely secure the transmission torque converter away from the engine flywheel/flexplate? |
Go to Step 5 | Go to Step 11 |
| 5 |
Did the flywheel/flexplate exhibit excessive lateral runout? |
Go to Step 8 | Go to Step 6 |
| 6 |
Did the flywheel/flexplate exhibit any of the conditions listed? |
Go to Step 8 | Go to Step 7 |
| 7 |
Has the disturbance been significantly reduced or eliminated? |
Go to Step 9 | Go to Step 11 |
| 8 |
Did you complete the tightening or replacement? |
Go to Step 20 | - |
| 9 |
Has the disturbance been significantly reduced or eliminated? |
Go to Step 20 | Go to Step 10 |
| 10 | Replace the out-of-balance transmission torque converter. Did you complete the replacement? |
Go to Step 20 | - |
| 11 |
Is the disturbance greater along the FRONT of the engine? |
Go to Step 19 | Go to Step 12 |
| 12 | Is the vehicle equipped with an automatic transmission? | Go to Step 18 | Go to Step 13 |
| 13 |
Does the engine flywheel clutch surface exhibit excessive lateral runout? |
Go to Step 18 | Go to Step 14 |
| 14 | 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 |
Do any of the above conditions exist? |
Go to Step 18 | Go to Step 17 |
| 16 |
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:
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 |