2010 Allison 1000 (MW7) Truck Transmission
2010Model Year Summary
Allison 1000 Series six-speed automatic truck transmission
Carryover Features and Benefits from 2009 model year
LOW MAINTENANCE
The Allison 1000 series are heavy-duty transmissions, where “fill-for-life” is not normally an operational priority. Fluid changes are scheduled into the typical maintenance of the light-duty applications, such as the Silverado and Sierra pickups. Maintenance is made easier since the transmission incorporates an external spin-on type fluid filter. The filter and fill ports are easily accessible. In addition, built-in electronic diagnostics help to identify potential reliability concerns.
An extra ratio was added to the 1000-series for 2006 for Chevrolet Silverado and GMC Sierra 2500 HD and 3500 models equipped with either the Vortec 8.1L or Duramax 6.6L, which created a first-in-class six-speed automatic for those vehicles.
The Allison 1000 Series six speed in Chevrolet Silverado and GMC Sierra 2500 HD and 3500 models features range selection mode. Range selection mode allows the driver to select the desired gears, via a thumb-activated switch on the shifter, providing 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 available only when the tow/haul mode is selected and the transmission is not in the range selection mode.
The Allison 1000 features the fourth generation of transmission control modules, which are smaller in size than the previous modules. They are mounted externally on the vehicle chassis, and a new 80-pin single wiring connector reduces connections and volume of wires, improving reliability and assembly.
The internal mode switch is built into the 1000 series, eliminating the need for the addition of a neutral/start/backup switch, which was formerly installed during vehicle assembly.A wiring feedthrough connector is used to connect the TCM to the internal mode switch and control valve body.
The torque converter clutch solenoid is a variable bleed solenoid. This type of solenoid allows very accurate control of the fluid pressure in the transmission. The 22-tooth fluid pump’soperating noise is at a low frequency that is masked by the noise of the engine.
Durability comes from a target lifespan of 200,000 miles, made possible through the use of larger, heavier components than are normally found in 1-ton pickups. Weight ratings for the transmissions exceed the maximum weight limits for the Silverado and Sierra pickups.
A driver-selectable “Tow/Haul” mode locks up the torque converter earlier (in 2nd and 3rd gears) to prevent excess heat gain from fluid shear, a normal condition for an unlocked torque converter. Normally, the torque converter locks up only in 4th and 5th gears. Also in Tow/Haul mode engine timing is retarded slightly during shifts to dampen torque transfer. The electronic controls also monitor when the vehicle is on a grade, and holds lower gears instead of upshifting. This takes advantage of engine braking when the vehicle is traveling downhill. The clutches in the transmissions are wear adaptive. This means sensors instruct the electronic controls to vary shift timing to compensate for normal wear of the clutch friction surfaces and normal tolerance variations within the transmission hardware. In addition, the electronics have a memory to store fault codes for easier diagnostics by a service technician. Finally, a fail-safe function allows the transmission to operate independent of electronic controls in third and reverse gears, should there be an electrical or battery failure.
There are two locations for Power Take Off (PTO) accessory drives to be mounted to the transmission. These accessories are common devices such as hydraulic pumps that are used to operate the dump body of a dump truck, or power generators, sewer cleaners, or airport refueling systems.