Heavy Vehicle Driveline Failure Document

Article 130926 / AGM Web-Page Heavy Vehicle Driveline Failure Document part of investigation review 1999 - 2013

7 September 2013/130927 Our Ref: File AGM-130912
Subject: Mitsubishi Shogun FS435S1 Heavy Transport Vehicle Transmission Driveline
Date of manufacture: 2000
Estimated km: 900,000 to 1,000,000
VIN: No: JMAFS25S0KN00028
Registration No: YU7728
Owners: Masonry Distributors (Auckland) Limited, Auckland (Company No. 859261)
Date of incident: September 2013
Place of incident: Auckland city, Auckland Harbour Bridge


The background information to this incident may or may not be held within the NZTA’s record file archive regarding the Auckland Harbour Bridge, as the truck and trailer concerned was at the highest point on the bridge expressway when the incident and failure occurred. The driver of the vehicle heard an audible metallic clatter, then there was a load bang within the drive-train and the truck lost power. The driver of the truck de-selected the transmission gears and coasted downhill under braking, and brought the vehicle to a controlled stop. The truck and trailer were later salvaged by a heavy vehicle transporter. It appears that no investigation was undertaken by the bridge highway patrol in this instance. However, the NZTA should hold information regarding another heavy vehicle incident on the Auckland Harbour Bridge, which was reported on the TV One website ( on 19 April 2013, the day it happened.

However, as for the more recent failure of a Mitsubishi heavy vehicle’s bellhousing and transmission, as identified in the enclosed exhibits, this was recently brought to the writer’s attention. The severe cracking of the transmission’s alloy bellhousing and the material breakage of the main body housing section of the transmission are but one more example of the type of fatigue failure to which these cantilevered transmissions have shown to be prone. Once more, the failure is similar to the one investigated by the writer in 2007; there have been many others.

Download the full report 140129_ASSESSCO_Eaton_Roadranger_Transmission_Failure.pdf

© Mitsubishi heavy vehicle bellhousing and transmission, subjected to metal fatigue and resultant catastrophic separation and catastrophic failure. Date recovered / 130912 additional evidence related to Eaton Roadranger cantilevered transmissions and subsequent material fatigue, and the subsequent loss of transmission alignment with the engine flywheel, causing premature failure of the selector forks and syncro components, due to driveline component drag. “THIS REPORT SUMMARY IS PREPARED FOR THOSE ENTITIES THAT MAY BE SUBJECTED TO A SIGNIFICANT LIABILITY CLAIM, SHOULD A SUDDEN CATASTROPHIC FAILURE OCCUR IN A HEAVY COMMERCIAL VEHICLE’S CANTILEVERED TRANSMISSION DRIVELINE, RESULTING IN INJURY OR DEATH. THIS WOULD RESULT IN A SIGNIFICANT LEGAL INQUIRY BY THE REGULATOR. THE KEY TO ELIMINATING THE POSSIBILITY OF SUCH AN EVENT OCCURRING IS THE RETROFITTING OF REAR SUPPORT MOUNTS FOR THE GEARBOX. FAILING THAT, THE KEY TO MINIMISING THE PROBABILITY OF CATASTROPHIC DRIVELINE FAILURES OCCURRING IS REGULAR CHECKING OF THE COMPONENTS FOR FATIGUE CRACKING.”