The numbers below refer to the step numbers on the diagnostic table.
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.
An engine flywheel/flexplate that has excessive lateral runout, when combined with the mass of the transmission torque converter, can produce a disturbance.
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.
This step is designed to isolate the transmission from the engine to determine if the disturbance is related to the engine ONLY.
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.
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.
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.
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.
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.
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.
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.
An engine flywheel/flexplate that is damaged, misaligned, and/or imbalanced, can produce a disturbance.
An engine crankshaft balancer that is damaged, misaligned, and/or imbalanced, can produce a disturbance.
Step | Action | Yes | No | ||||||||||||||
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Caution: Refer to Work Stall Test Caution in the Preface section. | |||||||||||||||||
1 | Were you sent here from the Vibration Analysis - Engine/Accessory Isolation table? | Go to Step 2 | |||||||||||||||
2 | Is the J 38792-A , Electronic Vibration Analyzer (EVA) 2, available? | Go to Step 3 | |||||||||||||||
3 | Is the vehicle equipped with a manual transmission? | Go to Step 11 | Go to Step 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 | |||||||||||||||
Did the flywheel/flexplate exhibit excessive lateral runout? | Go to Step 8 | Go to Step 6 | |||||||||||||||
Did the flywheel/flexplate exhibit any of the conditions listed? | Go to Step 8 | Go to Step 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 | -- | ||||||||||||||
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 | -- | ||||||||||||||
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 | ||||||||||||||
Does the engine flywheel clutch surface exhibit excessive lateral runout? | Go to Step 18 | Go to Step 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 | |||||||||||||||
Do any of the above conditions exist? | Go to Step 18 | Go to Step 17 | |||||||||||||||
Do any of the above conditions exist? | Go to Step 18 | ||||||||||||||||
Re-index the pressure plate to the engine flywheel. Did you complete the re-indexing? | Go to Step 20 | -- | |||||||||||||||
Replace the engine flywheel/flexplate. Did you complete the replacement? | Go to Step 20 | -- | |||||||||||||||
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 | |||||||||||||||
21 | Perform the Vibration Analysis - Road Testing table. Refer to Vibration Analysis - Road Testing . Is the disturbance still present? | System OK |