Shift Patterns
Shift Patterns
The vehicle is equipped with adaptive shift strategy. Whenever the battery has been disconnect for any type of service or repair, the strategy parameters stored in keep alive memory (KAM) 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 powertrain control module (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 powertrain control module (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 range selector lever). There are four 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.
Power Take-Off (PTO)
NOTE: Failure to install the wire from the powertrain control module (PCM) pin 322 to pin 294 will result in low line pressure leading to PTO and transmission failure.
Some 6.8L and 6.0L SuperDuty vehicles have power take-off (PTO) capability. During stationary operation in PARK or NEUTRAL, the torque converter is locked up when the PTO is ON and the engine operates at 1200 rpm. The following schedule shows expected rpm and line pressure while driving with the PTO in use.
All 2005 Super Duty F-Series vehicles equipped with a 6.0L diesel engine, TorqShift transmission and power take off (PTO) option, built before September 22, 2004, will exhibit insufficient transmission line pressure supplied during PTO operation. Symptoms include lack of torque converter lock up and transmission line pressure below 150 psi while in stationary PTO mode. PTO operation under this condition may result in PTO unit damage and subsequent TorqShift transmission damage is possible.
Reprogram the powertrain control module (PCM) and transmission control module (TCM) to the latest calibration using WDS release B33.6 or higher. If transmission damage occurs due to improper PTO function, follow normal Workshop Manual procedures to diagnose and repair. Clear diagnostic trouble codes if any and verify the repair.