Medium gearbox

THE NEW Fuller UltraShift HV automated transmission for medium-duty trucks completes Eaton Corporation's family of medium-duty transmissions, says Bill Gross, product manager for medium duty transmissions. It is designed specifically for those applications that have readily adopted automatic transmissions over the past 10 years, he says.

Available as a five- or six-speed transmission, the UltraShift HV — the HV standing for Highway Value — is designed to provide consistent fuel economy by letting the engine operate in the most fuel-efficient portion of its performance curve, Gross says. Although Eaton is not ready to release definitive fuel economy projections, he says that early tests have provided encouraging results. Automated mechanical transmissions are inherently more fuel efficient than planetary-geared transmissions with torque converters, because torque converters generate heat, robbing the drivetrain of power that otherwise could drive the vehicle, Gross says. Final data will not be complete until the new transmissions go into volume production in April 2006. A limited production run will build 500 UltraShift HVs between now and March 2006.

The UltraShift HV is a fully automated transmission using technology and automation components derived from Eaton's heavy-duty UltraShift line. No clutch activity is required to start from a standing stop. The medium-duty transmissions are designed for Class 6 and Class 7 diesel-powered vehicles with horsepower ranging from 195 to 260 and maximum torque output of 660 lb-ft for gross loads up to 33,000 pounds. Eaton officials say that pick-up and delivery applications are ideal for the automated gearboxes. For applications that require a power-take-off, the case of the mechanical transmission comes standard with a six-bolt PTO port.

In addition to fully automated operation, UltraShift HV transmissions have Hill Assist that automatically minimizes rollback on grades of up to 10% while the driver makes the transition from brake to accelerator pedal. Hill Assist was added to the transmissions during the development phase for the product after surveys with customers. The majority of customers asked about the potential usefulness of Hill Assist said it would be a top priority in the specifications for a medium-duty transmission, Gross says. Customers reportedly said that Hill Assist is more than a convenience; it results in safer operation in both uphill and downhill situations.

Gross says the medium-duty UltraShift HV is warranted for up to three years and unlimited mileage based on applications. Truck dealers can provide specific information about the warranty coverage for various vehicle applications. The warranty covers parts and labor.

The new transmissions are intended to last the projected life of most medium-duty trucks without major maintenance. For instance, all UltraShift HV gearboxes will be delivered already filled with a synthetic lubricant. Recommended change interval for the lubricant and transmission filter is 500,000 miles, so transmissions are effectively delivered already lubed for life.

Modular design speeds service

When service is required, the gearboxes are built with modular design to reduce service costs and provide more rapid service. In addition, Eaton has used a significant degree of commonality of electronic modules and shift controls from other Fuller manual and automated transmissions so that technicians need less specialized training and parts inventories can be smaller. Transmissions are protected from user abuse with electronic shift protection and clutch protection logic in the operating software to reduce the potential for drivetrain and clutch damage.

Transmissions are controlled by a third generation of Eaton's shift-by-wire electronic technology. The system takes an electronic snapshot, an automatic data picture of the system when a fault occurs. The system also performs an automatic wiggle test on electronic connections by simulating an operating environment with jarring and vibrations. A separate service port allows technicians to hook test equipment to the transmission without disturbing already connected wiring and components. Some system faults are difficult to replicate when the transmission is not actually operating. To make fault diagnosis easier for technicians, drivers can trigger a data logger to capture system performance for 10 seconds when a fault occurs.

After 20 years of development and more than eight years of fleet operation, Eaton is ready to take on the high performance general fleet market with its newest automated heavy duty transmissions, says Scott Steurer, product line manager for heavy duty transmission — performance/vocational. The proof of this readiness is in the new Fuller UltraShift LHP, a model aimed at linehaul high performance.

The new UltraShift LHP is a 13-speed gearbox with a selectable low starting gear with a ratio of 12.2:1. This 14th gear is designated with an “L” in the model nomenclature, Steurer says. In addition to the low starting gear, the new LHP has gathered gear ratios at the low and high end of the operating range for better starts and more efficient cruising. The gathered gears allow the engine to operate in a tighter rpm range for more efficient use of available power. Three reverse gears provide maneuver flexibility for hooking to a trailer and backing a combination into a dock.

“Although the LHP is aimed at the high performance segment of the market, it offers the same benefits found in the rest of the UltraShift family of transmissions, including improved driver satisfaction, easier driver recruiting along with lower training costs, and reduced maintenance costs,” Steurer says.

Proven gearbox components

The LHP is based on the proven RT family of Eaton transmissions. “Nothing inside the box is new,” Steurer says. “It provides fully automatic two-pedal operation and can handle torque output up to 1,750 lb-ft for loads up to 110,000 lb gross weight. Although the transmission has 13 speeds, customers need to understand that it is built for highway performance and is not intended for extended off-road use.”

The transmission can be used in fully automatic mode, or the driver can utilize a manual gear hold and control up-shifting and down-shifting.

Development of the LHP has been an 18-month project with road testing beginning in September 2004. Test trucks were placed in seven fleets and logged more than 800,000 total miles. Transmissions are available in limited quantities with 400 planned for production in the next six months. Full production is scheduled for the end of 2005.

Reduced driver training

Automated mechanical transmissions really prove their value by reducing driver training costs and improving the resale of used trucks. Typically, training time to use the transmission can be reduced 10 to 15 total hours, down from an industry average of 25 hours, Steurer says. A good benchmark for training costs is $500 per hour, he says. In addition, based on resale values for previous automated transmissions, the LHP should increase the residual value of a typical highway tractor by $3,500. Warranty for the LHP is five years or 500,000 miles.

That will be almost enough to recover the premium price of the LHP, which will carry a price tag of $3,300 more than a 13-speed manual transmission. Steurer is careful to note that the final purchase price is set by truck manufacturers, not Eaton Corporation.

Electronics, controls, and the shifter for the LHP are the same as the Generation AutoShift, so parts inventory can be reduced. The transmission starts automatically, using an industry-standard 15½-inch twin-plate ceramic clutch. Advanced electronics and completely automated operation reduce the potential for drivetrain abuse. In addition, the LHP has dual torque capacity, able to handle 1,650 lb-ft in the middle of the gear range and 1,750 lb-ft in the top two gears. The new electronics can take an electronic snapshot of the system when a fault occurs and it can capture 10 seconds of performance data when triggered by the driver, a feature that helps to diagnose faults that are hard to replicate in a service bay. Technicians can test the electronics using a separate service port so that system wiring need not be disturbed. In addition, the system can simulate its own wiggle test for wiring connections.

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