INVESTIGATION DISCLOSED THAT THE MANUFACTURER ISSUED A SERVICE BULLETIN IN AUGUST 2003, REGARDING SERVICE THAT REQUIRED REMOVAL OF THE WIPER ARMS.GM ISSUED THE BULLETIN AT THAT TIME TO ADDRESS CUSTOMER COMMENTS ON WINDSHIELD WIPER CHATTERING OR HOPPING ACROSS THE WINDSHIELD DURING WIPER OPERATION.THE CORRECTION WAS TO REPLACE THE WIPER ARM AND BLADE.HOWEVER, THE BULLETIN DID NOT PLACE SPECIFIC EMPHASIS ON THE IMPORTANCE OF USING THE PROPER TOOL AND PROCEDURES TO REMOVE THE WIPER ARM AND TO PREVENT DAMAGE TO THE PIVOT SHAFT HOUSING.IN GM'S RESPONSE TO ODI'S INFORMATION REQUEST LETTER, GM STATES, ...THE WIPER PIVOT HOUSING IN THE SUBJECT VEHICLE MAY CRACK AND/OR FRACTURE AS A RESULT OF AN OVERLOAD CONDITION APPLIED TO THE WIPER PIVOT HOUSING DURING IMPROPER REMOVAL OF THE WIPER ARMS.GM'S FIELD SURVEY FOUND THAT ...DEALERS DO NOT ROUTINELY USE THE WIPER ARM REMOVAL TOOL WHEN SERVICING THE WIPER ARMS.ODI CONCLUDES THAT THE FAILURE AND WARRANTY REPORTS IN THIS INVESTIGATION DO NOT IDENTIFY A SAFETY RELATED DEFECT TREND.ODI DOES HAVE CONCERN, HOWEVER, THAT PRIOR AND IMPROPERLY PERFORMED WIPER ARM REMOVAL MAY HAVE CONTRIBUTED TO THE FAILURES IDENTIFIED DURING THIS INVESTIGATION.IN AUGUST 2007, GM ISSUED A NEW TECHNICAL SERVICE BULLETIN (GM NUMBER 07-08-43-007) TO SPECIFICALLY EMPHASIZE THE IMPORTANCE OF USING THE PROPER TOOL FOR REMOVAL OF THE WIPER ARMS TO PREVENT PIVOT SHAFT DAMAGE DURING THE PROCEDURE.THIS INVESTIGATION IS CLOSED.