NHTSA Complaint #10447575 — 2000 MCI 102DL3

FIRST GROUP ALLEGES TO HAVE EXPERIENCED SEVERAL DRIVESHAFT FAILURES BEGINNING IN MARCH 2010 WHICH WERE NOT CONTAINED BY THE SAFETY LOOPS ON THE SUBJECT MCI BUSES. THEY BELIEVE THAT TWO OF THE EVENTS RESULTED IN MULTIPLE INJURIES AND FATALITIES DUE AN "UNLOCKED CONDITION" OF THE STEERABLE TAG AXLE AND A LOSS OF VEHICLE CONTROL. THE DESIGN IN QUESTION HAS BEEN IN PRODUCTION SINCE THE EARLY 1990S. A STEERABLE TAG AXLE IS USED TO INCREASE THE GVWR WHILE REDUCING THE TURNING RADIUS AND MINIMIZING THE TIRE SCRUB WHICH WOULD NORMALLY OCCUR WITH A TANDEM REAR AXLE CONFIGURATION. IN THIS CASE, THE TRANSMISSION COUPLES TO THE DRIVESHAFT WHICH THEN PASSES THROUGH A GUARDIAN STRUCTURE IN THE TAG AXLE AND A DEDICATED SAFETY LOOP BEFORE IT COUPLES TO THE DRIVE AXLE. INCREASED ENGINE LENGTH IN THE LAST 20 YEARS HAS SHORTENED THE DRIVESHAFT.