1999 Mci E4500

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.

This Service Bulletin informs affected owners of 1997-2013 E4500 and 2001-2015 J4500 model coaches equipped with Rear Axle Steering (RAS) system of the importance of maintaining tag axle caster, and provides the procedure to adjust the caster, if necessary.

This Service Bulletin informs affected customers that MCI was notified by Shaw Development that the diesel exhaust fluid (DEF) tank cap requires routine cleaning to prevent the potential for crystallization build up at the vent, which may result in potential vacuum issues which could result in collapsing of the tank walls on MCI D model coaches, MCI E4500 model coaches and MCI J4500 model coaches.

MOTOR COACH INC: DRIVE AXLE SUSPENSION SUPPORT STRUCTURE MAY ACCUMULATE WATER CAUSING SUPPORT STRUCTURE DAMAGE DUE TO EXPANSION, IN FREEZING TEMPERATURES, WHILE COACH IS BEING OPERATED. MODELS E4500, J4500. NO MODEL YEARS LISTED. *PE UPDATED 12/10/12. *PE

MOTOR COACH INDUSTRIES: ON SOME COACHES, WATER MAY MIGRATE ONTO/INTO THE TRANSMISSION AND/OR THE FILL TUBE, THROUGH THE BREATHER VENT THAT IS LOCATED ON TOP OF TRANSMISSION. NO MODEL YEARS LISTED. *PE

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