September 2008, Work Truck - Feature
Avoiding the Pitfalls in Spec'ing Powertrains & Transmissions
By Joe Bohn
Diesel vs. Gasoline
The combination of today’s higher diesel fuel and engine costs has impacted trade-in/resale prices of diesel-powered trucks, reducing their value at auctions.
"A person going into the secondary market is looking to spend as little as they can. They’re buying a truck that’s only going to give them a few additional years of life, and they’re looking at an engine that costs $3,000 more and fuel costing nearly $5 per gallon," says PHH’s Mathai.
"A few years ago, you could get your money back on a diesel. As things have changed, I don’t think they’ll bring much more at auction," he notes.
Historic perceptions about the long-term reliability and durability differences between diesel and gasoline engines are no longer valid.
"Today, it’s not uncommon for a properly maintained gasoline engine to last 150,000-200,000 miles, and sometimes more, before requiring a rebuild," says Vivek Khosla, PHH Arval’s director of product management for trucks.
Khosla
"While diesel engines still have a longer life, it may be more cost-effective for vehicles carrying light to moderate loads to purchase a truck with a gasoline engine, given that diesel engines are significantly more expensive and diesel costs are more than 20 percent more expensive than gas today," Khosla says.
He adds, "With V-8 and V-10 gasoline engines, trucks today can also generate sufficient torque to pull moderate loads."
Traditional thinking about the cost-effectiveness of diesels has changed dramatically. Automatically assuming they are the best choice for trucks in the 8,600-lb. to 19,000-lb. GVW range can be a big mistake.
The high cost of diesel has eliminated the fuel economy savings of a diesel truck. Mathai says PHH doesn’t recommend selecting a diesel truck except in cases in which the engine is subject to prolonged idling when power from the transmission is required to operate equipment such as cranes, air compressors, etc.
If the engine is subject to extensive idling throughout the day, the diesel, which typically idles at a lower rpm and consumes about one-fourth the fuel of a gasoline engine at its low rpm, remains the better choice.
Similarly, a fleet with on-site diesel fueling provisions will likely find it more cost-effective to continue purchasing diesel trucks, rather than installing costly new gasoline storage tanks.
Automatic vs. Manual
Despite their lower cost appeal, spec’ing manual transmissions for medium-duty trucks is typically a mistake, including vehicles up to the 33,000-lb. GVW range, as well as those in lower ranges.
As ARI’s Duford points out, "Driver availability and efficiency are the big stumbling blocks. There’s no pool of drivers who know how to drive a manual. If someone is not adept and runs out the gears too long, he can run up costly repair bills, such as clutch damage."
Automatic transmissions also provide better towing capability and trade-in or resale value than manuals.