The Duramax 6600 also has a new intake air heater to reduce smoke and emissions during cold or light-load driving, Freese explains. "The system
features a 1000-watt grid heater located in the air intake duct, which is triggered automatically by the engine controller. It heats up the incoming air to speed warm-up of the engine."
The new Allison 1000 transmission is part of GM's rollout of 10 six-speed automatic transmission variant by the end of the decade, Freese says, which will be good news for consumers since this application certainly has significant benefits.
The Allison 1000 reduces engine speed by 250 rpm at 102 kmh, which should increase fuel economy and range. It also comes with the first-in-class tap-shift range-selection feature that allows the driver to "easily select the desired gears for greater control."
Changes to the Allison 1000 represent a "best of all worlds' scenario," says Kevin Wayman, the transmission's chief engineer. ''Performance, quietness and fuel mileage are all enhanced without degradation to product durability."
The sixth gear is essentially a second overdrive gear, Wayman explains, and that "enables a wide, 5.08:1 overall forward gear ratio coverage and allows the vehicle's engine to operate at lower rpm, particularly during higher-speed driving on highways and freeways." Its 0.61 ratio sixth gear provides a 1550-rpm engine speed at 102 kmh, compared with the five-speed transmission's 1800-rpm engine speed at the same speed.
The ratios of gears one through five remain the same as the Allison 1000 five-speed, Wayman says, including the 0.71:1 fifth gear.
The range-selection feature allows the driver to select the desired gears, via a thumb-activated switch on the shifter, says Wayman, and that provides "a feeling of enhanced control in unique driving situations, such as towing on a steep grade."
The range selection feature holds the gear pre-selected by the driver and electronic safeguards prevent the transmission from being shifted in a manner that could cause engine damage or loss of vehicle control. Grade braking and cruise grade braking are only available when the tow/haul mode is selected and the transmission is not in the range selection mode.
In addition to the sixth gear and range selection feature, says Wayman, the Allison 1000 also benefits from complementary upgrades that include:
The Allison 1000 also has a unique, GM-patented elevated idle mode, which allows for faster interior warm-up of diesel-equipped vehicles. "The system is synchronized with the engine and activated through the vehicle's driver information center, Wayman says. As a result, "When elevated idle is active, the transmission increases the load on the engine so that it will generate heat more quickly and warm the interior in less time."
photo:General Motors
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| GM Duramax 6600 diesel (photo: General Motors) |
The new Allison 1000 transmission is part of GM's rollout of 10 six-speed automatic transmission variant by the end of the decade, Freese says, which will be good news for consumers since this application certainly has significant benefits.
The Allison 1000 reduces engine speed by 250 rpm at 102 kmh, which should increase fuel economy and range. It also comes with the first-in-class tap-shift range-selection feature that allows the driver to "easily select the desired gears for greater control."
Changes to the Allison 1000 represent a "best of all worlds' scenario," says Kevin Wayman, the transmission's chief engineer. ''Performance, quietness and fuel mileage are all enhanced without degradation to product durability."
The sixth gear is essentially a second overdrive gear, Wayman explains, and that "enables a wide, 5.08:1 overall forward gear ratio coverage and allows the vehicle's engine to operate at lower rpm, particularly during higher-speed driving on highways and freeways." Its 0.61 ratio sixth gear provides a 1550-rpm engine speed at 102 kmh, compared with the five-speed transmission's 1800-rpm engine speed at the same speed.
The ratios of gears one through five remain the same as the Allison 1000 five-speed, Wayman says, including the 0.71:1 fifth gear.
The range-selection feature allows the driver to select the desired gears, via a thumb-activated switch on the shifter, says Wayman, and that provides "a feeling of enhanced control in unique driving situations, such as towing on a steep grade."
The range selection feature holds the gear pre-selected by the driver and electronic safeguards prevent the transmission from being shifted in a manner that could cause engine damage or loss of vehicle control. Grade braking and cruise grade braking are only available when the tow/haul mode is selected and the transmission is not in the range selection mode.
In addition to the sixth gear and range selection feature, says Wayman, the Allison 1000 also benefits from complementary upgrades that include:
- upgraded 310-mm torque converter that improves torque capacity
- new 22-tooth pump that reduces noise, vibration and harshness
- new solenoids provide better converter lock-up control and shift feel
- upgraded rotating clutch that improves torque capacity, and
- new A40, 32-bit transmission control module
The Allison 1000 also has a unique, GM-patented elevated idle mode, which allows for faster interior warm-up of diesel-equipped vehicles. "The system is synchronized with the engine and activated through the vehicle's driver information center, Wayman says. As a result, "When elevated idle is active, the transmission increases the load on the engine so that it will generate heat more quickly and warm the interior in less time."
photo:General Motors
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