Advances in lower numeric axle ratings and higher torque engines are putting a lot more strain on drivelines - and trucking fleets are being warned about it. At the fall meeting of The Maintenance Council (TMC) of the American Trucking Associations, Robert C Morgillo headed up a task force that will urge trucking fleets to perform closer inspections on driveline fasteners every 100,000 miles and to retorque them if needed.
"There's a lot more torque out there in today's engines, and as axle ratios get lower, that means there will be a lot more flex being transmitted to the driveline," said Morgillo, warranty and technical support manager for Dana Corp's Spicer Driveshaft Division. He is head of a TMC task force on driveline fasteners.
"The twisting activity is increased to the driveline mainly because of the high start-up torque of today's engines," said Morgillo. Higher torque engines and lower axle ratings are here to stay, too, he said, as they contribute to better fuel economy. However, dropping out the entire driveline every 100,000 miles to make sure the fasteners are secure would be prohibitively expensive in terms of labor man-hours.
Morgillo's task force recommends that fleet technicians check the tightness of driveline fastener washers and look for "fretting," the leading sign of corrosion in a fastener. That way, fastener wear can be detected without preventive maintenance practices while eliminating the threat of driveline failure.