Suspension noise, struts or alignment

THIS INVESTIGATION WAS OPENED BASED ON 78 CONSUMER COMPLAINTS OF SEVERE SUSPENSION AND STEERING WHEEL OSCILLATIONS AFTER THE SUBJECT VEHICLES TRAVELED OVER AN UNEVEN SURFACE.ODI WAS CONCERNED ABOUT THESE COMPLAINTS BECAUSE MANY OF THEM ALLEGED LOSS OF CONTROL AND THE LOSS OF CONTROL OCCURREDAT SPEEDS ABOVE 50 MILES PER HOUR.AT THE TIME THESE COMPLAINTS WERE RECEIVED, ODI WAS ALSO AWARE OF THE TSB 07-10-10 AND EARLY WARNING FIELD REPORTS THAT DISCUSSED THE SHIMMY CONDITION ON THE SUBJECT VEHICLES.SINCE OPENING THIS INVESTIGATION, ODI HAS CONFIRMED, BASED ON CONSUMER COMPLAINTS, WARRANTY DATA, TESTING CONDUCTED BY VRTC, AND ODI INSPECTION OF COMPLAINT VEHICLES, THAT THE OWNERS OF THE SUBJECT VEHICLES ARE EXPERIENCING SHIMMY EVENTS ON THEIR VEHICLES.HOWEVER, ODI HAS ALSO CONFIRMED THAT OWNERS TYPICALLY DO NOT MAINTAIN THEIR TIRES AT THE PRESSURES RECOMMENDED BY FORD ON THE TIRE LABEL.FURTHER, ODI HAS FOUND THAT IN ORDER FOR SHIMMY TO OCCUR, TIRE PRESSURES MUST BE SUBSTANTIALLY BELOW (AT LEAST 20%) THOSE SPECIFIED ON THE VEHICLE TIRE LABEL.ODI CONSIDERS THESE UNSAFE TIRE CONDITIONS TO BE THE RESULT OF ONE OF THREE TYPICAL SITUATIONS.THE TIRES ARE BEING IMPROPERLY MAINTAINED, THE OWNERS ARE INTENTIONALLY SETTING THE TIRE PRESSURES LOW TO ENHANCE RIDE QUALITY, OR AFTERMARKET TIRES (NOT DESIGNED FOR USE ON THE VEHICLE) ARE INSTALLED TO CHANGE THE APPEARANCE OR FUNCTION OF THE VEHICLE.THE SUBJECT VEHICLES ARE INTENDED AND DESIGNED TO BE USED AS HEAVY DUTY VEHICLES AND AS SUCH REQUIRE

ODI HAS RECEIVED 78 CONSUMER COMPLAINTS OF SEVERE SUSPENSION AND STEERING WHEEL SHIMMY AND OSCILLATIONS COMMENCING AFTER THE SUBJECT VEHICLES TRAVELED OVER AN UNEVEN ROAD SURFACE. THE MAJORITY OF THESE INCIDENTS OCCURRED AT SPEEDS OF 50 MPH OR GREATER.THIRTEEN OF THE COMPLAINTS RECEIVED BY ODI ALLEGE LOSS OF STEERING CONTROL AND THAT THE VEHICLE CHANGED DRIVING LANES UNCONTROLLABLY.FOUR OF THE COMPLAINTS RECEIVED BY ODI ALLEGE THAT THE VEHICLE LEFT THE ROAD SURFACE AS A RESULT OF THE VIOLENT SUSPENSION AND STEERING WHEEL OSCILLATIONS.IN ONE CASE THE CONSUMER ALLEGES THAT AFTER THE VEHICLE LEFT THE ROAD SURFACE, IT CRASHED INTO A WOODED AREA.ADDITIONALFACTORS CONTRIBUTING TO THE OPENING OF THIS EA WERE EARLY WARNING FIELD REPORTS,SUBMITTED BY FORD, DESCRIBING SUSPENSION SHIMMY / OSCILLATIONSAND A FORD TSB (07-10-10) DESCRIBING THE SUSPENSION SHIMMY ISSUE AND HOW TO REPAIR THE PROBLEM.FORD HAS DESCRIBED SHIMMY AS SELF-EXCITED OSCILLATION OF THE STEERING WHEELS WITH ACCOMPANYING WHEEL TRAMP.THIS PE HAS BEEN UPGRADED TO AN ENGINEERING ANALYSIS (EA) TO DETERMINE IF THE SHIMMY CONDITION THAT OCCURS ON THE SUBJECT VEHICLES CREATES A CONDITION WHERE THE VEHICLE BECOMES DIFFICULT TO CONTROL OR STARTLES THE DRIVER, THUS PRESENTING A SAFETY RISK.

CONSUMER COMPLAINTS REPORT THAT BOLTS WHICH RETAIN THE AXLE PIVOT BRACKET TO THE FRAME CROSS MEMBER CAN LOOSEN OR FAIL, CAUSING THE INBOARD END OR THE AXLE TO BECOME DETACHED FROM THE VEHICLE.OWNERS ALLEGE THAT THIS COULD RESULT IN LOSS OF STEERING CONTROL, HOWEVER THE COMPLAINT DATA SHOWS ONLY ONE INCIDENT WHERE THE VEHICLE LEFT THE ROADWAY FOLLOWING AXLE SEPARATION, WITH NO DAMAGE TO THE VEHICLE.IN ADDITION TO THE 225 CONSUMER COMPLAINTS, THERE WERE 4,315 WARRANTY CLAIMS RELATED TO THE FRONT SUSPENSION AND MEMBERS, AND 22 VEHICLES WERE REPLACED FOR GOODWILL.DOCUMENTS SUBMITTED BY FORD, UNDER REQUEST FOR CONFIDENTIAL TREATMENT INDICATE THAT THE BOLTS WERE INADEQUATE FOR THE DURABILITY REQUIREMENTS OF THE VEHICLE.ALSO, BOLTS WERE FOUND TO HAVE BEEN INADEQUATELY TORQUED AT ONE OR MORE ASSEMBLY PLANTS.OTHER FACTORS, SUCH AS WAX TREATMENT OF THE FRAME, CONTRIBUTED TO THE PROBLEM.INCREASED BOLT DIAMETER AND INCREASED TORQUE APPARENTLY CORRECTED THE PROBLEM.A SERVICE BULLETIN, 96-20-13, WAS ISSUED TO ADVISE DEALERS OF THIS CORRECTIVE ACTION.IN THESE DOCUMENTS, FORD ALSO REPORTED THAT A VEHICLE, EQUIPPED FOR SIMULTANEOUS CATASTROPHIC FAILURE OF ALL PIVOT BRACKET FASTENERS, WAS EVALUATED RESULTING IN A SLIGHT VEHICLE PULL TO ONE SIDE WITH NO LOSS OF VEHICLE CONTROL.ODI HAS NOT REPLICATED FORD'S VEHICLE TESTING, HOWEVER ANALYSIS OF THE DESIGN OF THE FRONT SUSPENSION INDICATES THAT EVEN IF THE INBOARD END OF THEAXLE BECAME DISCONNECTED FROM THE FRAME, THE OUTBOARD END WOULD REMAIN FIR