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Allison 1000 Series Transmission

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The Duramax gets class-leading power and torque for 2011, and the Allison 1000 Series trans has been beefed to handle it. The new 30,000 psi, piezo-activated injectors not only give the D-Max the capability to safely run B20 biodiesel blends, they allow double pilot injection to make the engine considerably more quiet than before and around 11 percent more fuel-efficient. It also gets a heavy dose of improved internal parts, including more beef in the block, stronger connecting rods, stronger (but lighter) pistons, improved main bearings and a higher-pressure oil pump. To handle the enhanced Duramax, the Allison gets stronger input and output shafts, a stronger housing and a higher capacity torque converter. Even more significant is the new converter lockup strategy keeps it locked longer to reduce transmission heat and increase fuel economy.