Shift Patterns

Shift Patterns

The vehicle is equipped with adaptive shift strategy. Whenever the battery has been disconnected for any type of service or repair, the strategy parameters stored in keep alive memory will be lost. The strategy will start or relearn once the battery is reconnected and the vehicle is driven. This is a temporary condition and normal operating mode will be resumed once the PCM relearns all the parameters from the driving conditions. There is no set time frame for this process.

The customer must be notified that they may experience slightly firm upshifts, delayed or early shifts. This operation is considered normal and will not affect the function or durability of the transmission. As the PCM relearns, this temporary condition will be replaced by normal operating condition.

The transmission upshifts and downshifts are firmer with tow/haul ON than when tow/haul is OFF.


Upshifts

Transmission upshifting is controlled by the PCM. The PCM receives inputs from various engine or vehicle sensors and driver demands to control shift scheduling, shift feel and Torque Converter Clutch (TCC) operation.


Downshifts

Under certain conditions the transmission will downshift automatically to a lower gear range (without moving the transmission selector lever). There are 4 categories of automatic downshifts; Coastdown, Torque Demand, Forced or Kickdown shifts and grade braking.


Coastdown

The coastdown downshift occurs when the vehicle is coasting down to a stop.


Torque Demand

The torque demand downshift occurs (automatically) during part throttle acceleration when the demand for torque is greater than the engine can provide at that gear ratio.


Kickdown

For maximum acceleration, the driver can force a downshift by pressing the accelerator pedal to the floor. A forced downshift into a lower gear is possible below calibrated speeds. Specifications for downshift speeds are subject to variations due to tire size, engine and transmission calibration requirements.


Grade Braking

During tow/haul operation, depending on conditions, automatically scheduled downshifts may occur to increase the level of engine braking, particularly on down grades.