NHTSA Engineering Analysis EA04011

IN A LETTER DATED APRIL 20, 2005, GM NOTIFIED NHTSA THAT IT HAD DECIDED THAT DEFECTS THAT RELATE TO MOTOR VEHICLE SAFETY EXIST IN CERTAIN MODEL YEAR (MY) 1999-2002 C/K 1500 SERIES (PBR PARKING BRAKE SYSTEM) AND MY 2001-2005 C/K 2500 AND 3500 SERIES (TRW PARKING BRAKE SYSTEM) PICKUPS WITH MANUAL TRANSMISSIONS.ACCORDING TO GM, SOME OF THESE VEHICLES MAY HAVE CONDITIONS THAT CAUSE THE FRICTION LININGS TO WEAR TO AN EXTENT WHERE THE PARKING BRAKE CAN BECOME INEFFECTIVE IN IMMOBILIZING A PARKED VEHICLE.GM'S ACTION COVERS AN ESTIMATED TOTAL OF 142,585 VEHICLES.DEALERS WILL INSTALL A LOW-FORCE SPRING CLIP RETAINER FOR VEHICLES EQUIPPED WITH THE PBR PARKING BRAKE SYSTEM AND INSTALL A REDESIGNED PARKING BRAKE CABLE ASSEMBLY ON VEHICLES EQUIPPED WITH THE TRW PARKING BRAKE SYSTEM. A TOTAL OF 58 NON-DUPLICATIVE COMPLAINTS WERE RECEIVED BY ODI AND GM CONCERNING THE APPROXIMATELY 59,000 MY 1999-2002 C/K 1500 SERIES PICKUP TRUCKS WITH THE PBR PARKING BRAKE SYSTEM.THESE INCLUDED 22 ALLEGED ROLLAWAY INCIDENTS, RESULTING IN A RATE OF 38.5 ROLLAWAY INCIDENTS PER 100,000 VEHICLES.ODI IS AWARE OF 24 COMPLAINTS REGARDING THE MY 2001-2005 C/K 2500 AND 3500 SERIES MANUAL TRANSMISSION TRUCKS RECALLED BY GM, INCLUDING 5 ALLEGING ROLLAWAY INCIDENTS.THOUGH THE CONDITIONS DESCRIBED IN GM'S LETTER ARE ALSO PRESENT IN THE C/K TRUCKS WITH AUTOMATIC TRANSMISSIONS, THE ROLLAWAY RATE IN THOSE VEHICLES WAS SIMILAR TO THOSE OBSERVED IN PEER VEHICLES STUDIED BY ODI IN THIS INVESTIGATION.THIS ENGINEERING ANALYSIS IS CLOSED. FOR ADDITIONAL INFORMATION, SEE THE ATTACHED CLOSING REPORT.