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NHTSA Office of Defects Investigation

Engineering Analysis EA12-007: MCI Drive Shaft Safety Loop Failures

  • Closed

NHTSA's Office of Defects Investigation opened Engineering Analysis EA12-007 on September 13, 2012 and closed it on December 3, 2015. NHTSA's investigations file lists 24 models from 2 makes for it and links recall 14V-335 to it.

Updated daily from NHTSA's investigations file

Key facts

NHTSA number
EA12-007 (also written EA12007)
Investigation type
Engineering Analysis A more detailed stage of a defect investigation, opened when NHTSA's Office of Defects Investigation decides an issue merits further review, often after a Preliminary Evaluation or a Recall Query; it can include vehicle testing, surveys and further information requests.
Status
Closed December 3, 2015
Opened
Closed
Vehicle or equipment manufacturer
Motor Coach Industries
Components
Power Train — Driveline; Suspension — Multiple Axle; Suspension — Rear — Axle — Non-Powered Axle Assembly
Recall linked by NHTSA
  • 14V-335: Driveshaft may Detach from Motor Coach, reported
Vehicles and equipment
24 models from 2 makes, including the MCI D4000 and MCI D4500

NHTSA's summary

As NHTSA's Office of Defects Investigation wrote it for Engineering Analysis EA12-007.

try.vin does not copy NHTSA's investigation documents; NHTSA's investigation record lists the ones NHTSA has published.

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.

Vehicles and equipment listed for this investigation

NHTSA's investigations file lists these vehicles and equipment for Engineering Analysis EA12-007. A listed model year means only that an investigation names it; it says nothing about any particular vehicle. Model years with a try.vin recall page link to that page's NHTSA investigations section.

MCI

All MCI recalls

Motor Coach

  • Motor Coach 102 DL3

    • 1998, 1999, 2000, 2001

What an NHTSA investigation is

NHTSA's Office of Defects Investigation (ODI) looks into possible safety defects in vehicles and equipment, often after owner complaints. An investigation usually starts as a Preliminary Evaluation, or as a Recall Query when it concerns whether an existing recall covers the right vehicles or fixes the problem, and ODI can upgrade it to a more detailed Engineering Analysis. A Defect Petition asks NHTSA to open an investigation, and Audit and Equipment Queries are administrative investigations into whether companies complied with federal vehicle safety requirements, such as reporting, recall and certification rules.

An open investigation is not a finding that a safety defect exists, and NHTSA can close one without a recall.

To see whether a specific vehicle has an open recall, enter its VIN at nhtsa.gov/recalls.

Free VIN check: decode a VIN to see its year, make and model.

Sources

NHTSA's investigation record for EA12-007

Investigation details come from NHTSA's investigations file, which try.vin imports once a day. The investigation types are described from the U.S. Department of Transportation Inspector General's May 2023 report on NHTSA's Office of Defects Investigation, NHTSA's petition rules (49 CFR Parts 552 and 557) and NHTSA's Office of Defects Investigation procedures. How try.vin reads NHTSA investigations.