2006 Mci D4500

In the fall of 2011, network contacts made ODI aware of four (4) incidents of drive shaft failure on the subject buses involving a loss of vehicle control.Two of the incidents were relatively low speed non-crash events; and two resulted in motor coach rollovers.All four events showed signs of a common failure mode.The incidents and crashes studied during this investigation all resulted from a series of complex events that began with the the yoke journal ears on the drive shafts fracturing.Once the drive shaft failed. it was not adequately contained by a drive shaft safety loop or structure.The spinning and unrestrained drive shaft caused severe damage to components on the steerable tag axle at the rear of the vehicle and created a forced steering condition.Once the rear of the bus was being forcibly steered by the tag axle, the driver lost control of the vehicle.These conclusions are based on the forensics evidence and testing conducted by the Vehicle Research and Test Center (VRTC).The VRTC test report is attached to this closing resume that provides details on how the test center was able to conclusively identify the defective components on the buses and demonstrate the sequence of events that caused the buses to crash.Prior to the drive shaft failure events, there were no indications of improper maintenance or that maintenance was required that would have prevented the incidents.Additionally, the U-joints on the incident vehicles were found to be in good working condition at the time of the failure. Finally, records of driver interviews indicated a sudden onset of the failure with no warning.Following the VRTC testing, MCI issued recall 14V-335 involving certain model year 1993-1995 102DL3 motor coaches manufactured November 1992 to January 1995, and 2006 and 2008 D4505 motor coaches manufactured June 2005 to April 2008.The affected buses are equipped with a drive shaft with a compressed length of 30 inches or less (allowing it to escape containment if it fails), a steerable trailing tag axle equipped with a system that changes the axle caster when the vehicle is in reverse travel and no electronic stability control (ESC).Recall 14V-335 addresses the concerns of this investigation.The ODI report cited above can be viewed at www-odi.nhtsa.dot.gov/owners/SearchNHTSAID: ODI Number 10447575.

ODI has identified certain MCI coaches with powertrain configurations that may allow a driveshaft separated at the rearward universal joint to escape the guardian structure of the steerable tag axle and damage steering and braking components.The damaged components may increase the risk of a loss of vehicle control. The subject coaches include 806 model year 1992 through 2012 MCI D and E series motor coaches with steerable tag axles.This Preliminary Evaluation is being upgraded to an Engineering Analysis (EA12-007) to further study the alleged defect and to determine if a safety defect exists. The ODI report cited above can be viewed at www-odi.nhtsa.dot.gov/owners/SearchNHTSAID: ODI Number 10447575.

THIS INVESTIGATION WAS PROMPTED BY A REVIEW OF SERVICE BULLETINS PROVIDED BYMCI TO THE AGENCY. MOTOR COACH INDUSTRIES (MCI) SUBMITTED A SERVICE BULLETIN/PRODUCT IMPROVEMENT CAMPAIGN (#3016) IN THEIR 579.5 MONTHLY SUBMISSION REGARDING AN ALTERNATOR CABLE CHAFING ISSUE ON D SERIES COACHES EQUIPPED WITH A CATERPILLAR C13 ENGINE AND A 50DN DELCO ALTERNATOR. THE BULLETIN REPORTED THE CABLE CAN CHAFE AGAINST AN ENGINE BRACKET OR AS A RESULT OF MOVEMENT WITHIN THE CABLE CLAMPS.THE CORRECTIVE ACTION IS TO INSTALL A NEW CABLE AND SUPPORT BRACKETS.ODI BELIEVES THAT THERE IS A HIGH RISK FOR A THERMAL EVENT RESULTING FROM ALTERNATOR CABLES CHAFING WITHIN THE ENGINE COMPARTMENT.ODI PLACES INCREASED EMPHASIS ON PREVENTING POTENTIAL FIRES INVOLVING MOTOR COACHES AND OTHER VEHICLES WHICH CARRY LARGE NUMBERS OF PASSENGERS.IN NOVEMBER2009, MCI FILED A SAFETY RECALL (09V-346) OUTLINING THEIRREMEDY PROGRAM TO RESOLVE THIS ISSUE. MCI WILL INSTALL A NEW CABLE WITH A HEAVY DUTY TERMINAL THAT DOES NOT HAVE A SPIRAL LOOM OVER THE CABLE PASSING THROUGH THE CABLE CLAMPS.ALSO, THE NEW CLAMP AND MOUNTING BRACKET WERE CHANGED TO BETTER ALIGN THE CABLE AS IT PASSES THROUGH THE CABLE CLAMP THUS PREVENTING A CHAFING CONDITION. THE ACTION TAKEN BY MCI RESOLVES THIS INVESTIGATION.ACCORDINGLY, THIS INVESTIGATION IS CLOSED.

This Technical Service Information Bulletin (TSIB) describes an update from Meritor for the bolt torque application requirements on hub-to-rotor bolts for the front, drive and tag axles, on specific coaches equipped with Meritor EX225 disc brakes, on either Conventional, PreSet or Unitized Wheel-End hubs.

This Service Bulletin informs owners of the procedure to clean the batteries and reapply corrosion inhibitor every 6000 miles or 3 months, whichever first occurs.

MOTOR COACH INDUDSTRIES: INFORMATION ON REPLACING THE COOLANT PUMP THAT MAY HAVE A PROBLEM. *RM

MOTOR COACH INDUSTRIES SERVICE CAMPAIGN: SEE DOCUMENT SEARCH BUTTON FOR OWNER LETTER. THERE MAY BE A HARSH DOWNSHIFT, RPM FLARE, OR THE TRANSMISSION MAY LOCK. *RM

ZF FRIEDRICHSHAFEN: TAG AXLE/DRIVE SHAFT INTERFERENCE-DETROIT DIESEL SERIES 60 ENGINE AND ZF TRANSMISSION. EXPERIENCE INTERFERENCE BETWEEN DRIVE SHAFT U JOINT BEARING CAP BOLTS AND TAG AXLE CENTER BEAM. MODEL YEARS UNKNOWN. *PE

MOTOR COACH: TAG AXLE/DRIVESHAFT INTERFERENCE-FIXED TAG AXLE. INTERFERENCE DUE TO LIMITED CLEARANCE BETWEEN DRIVE SHAFT U JOINT BEARING CAP BOLTS AND TAG AXLE CENTER BEAM. MODEL YEARS UNKNOWN. *PE