Allison set to unveil 10-speed auto

INDIANAPOLIS, IN — You won’t see it for about a year, but Allison is keen to let you know it’s coming: a direct competitor for Eaton’s UltraShift Plus 10-speed. 

The TC10 TS (for tractor series) will be aimed primarily at short-haul and regional tractors that run on-highway but see a lot of gear shifting, as well as some vocational tractors that don’t go off road, said product specialist Todd Dygert during a recent unveiling at Allison’s Indianapolis headquarters.

It will provide performance and fuel economy superior to that of competitors’ products, the company says. It weighs 1030 lb, with overall system weight about the same as a 13-speed Eaton UltraShift Plus.

As a transmission for class 8 tractors, the TC10 will complement but not replace Allison’s fully automatic 4000 RDS (rugged duty series) transmissions that see on/off-road service in straight trucks. The 4000 HS (highway series) works well for some heavy on-highway applications but is not a good fit for long-haul road tractors, said Jim Wanaselja, vice president for North Ameircan sales and service. But the TC10 will be.

The TC10 combines a torque converter with a sophisticated 10-speed mechanical gearbox to achieve easy starts and smooth, fast shifting.

Along with ‘torque converter’, the ‘TC’ in the name also refers to ‘twin countershaft’ in the main gearbox’s mechanical layout. Power flow alternates among the counter- and mainshafts, depending on what gear it’s in, Dygert explained.

Engine power is continuously delivered via wet clutches — five in the main 5-speed gearbox and two in the 2-speed range box. The range box also uses planetary gears and a synchronizer, for forward-to-reverse stationary shifts only. With its ‘power shifting’ ways, there’s a constant flow of power and torque during gear changes, and that contributes to brisk acceleration.

The TC10’s main competition will be Eaton’s UltraShift Plus 10-speed as well as the Volvo/Mack I-Shift/mDrive, both of them increasingly popular automated mechanical transmissions. Their power-interrupt shifting is seen by Allison people as a detriment to both performance and economy. Each power pause causes the vehicle to momentarily lose momentum that the engine must then recover, burning an extra bit of fuel each time, Allison people contend.

Durability and cost were among development goals, Dygert said. The TC10 will be warranted for five years and 750,000 miles (1,207,000 km). All components, including the wet clutches, are intended to last the life of a transmission. The only scheduled maintenance is a changing of the synthetic fluid at 500,000 miles (805,000 km).

It will initially be rated for use with engines making up to 600 hp and 1650 lb ft of torque, with a higher torque rating to follow.

Early development and demonstration units now running have straight-cut gears but production TC10s will have helical gears with quieter angled teeth. Six TC10s are now being evaluated by customers in regular service, Dygert said.

The TC10 will be sold to truck makers for less than an Allison 4000, and at a price targeted to be competitive with existing automated mechanical transmissions. ‘Competitive’ here means "acquisition cost plus value," representatives said, noting that OEMs always set final component prices.

Because the TC10’s control module communicates via a J1939 data bus, it will work with any electronically controlled on-highway diesel, said Steve Spurlin, executive director, application engineering and vehicle integration. Allison expects to be working with most major OEMs as production begins in October 2012 and ramps up in 2013. — with files from Tom Berg at Heavy Duty Trucking

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