High Speed 1st Order Propshaft Vibration - keywords shake vibrate
| Subject: | High-Speed 1st Order Propshaft Vibration |
| Models: | 2005 Chevrolet Silverado C1 2WD Crew Cab Model C15543 |
| 2005 GMC Sierra C1 2WD Crew Cab Model C15543 |
| Equipped With a 3.73 Gear Ratio RPO GT4 |
This PI is being superseded to update models. Please discard PIP3347.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern:
A customer may have a concern with a 1st order propshaft vibration at very high vehicle speeds. This condition may occur at speeds of 95 MPH (153 KPH) or above. This condition may be caused by propshaft imbalance, and may be aggravated by driveline wear and/or accumulation of mud or ice.
Recommendation/Instructions:
Important: DO NOT attempt to duplicate this high speed condition on the road or on the hoist.
Check the balance of the propshaft using the procedure in SI (Document #688788), at normal road speeds. Check for contributing factors such as abnormal driveline wear or mud or ice accumulation, and repair as needed.
Reprogram the PCM with the latest available calibration. This calibration reduces the top speed attainable by the vehicle by 4 MPH (6 KPH). This calibration is the same as the one used in production of vehicles built after December 8th, 2004. Therefore, after reprogramming, the top speed capability of the vehicle is the same as current build vehicles. Vehicles built after December 8th, 2004 will not benefit from reprogramming the PCM.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed.
