COMPUSHIFT Mini Manual – COMPUSHIFT Mini Manual
Tuning and Driving
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The is the slowest speed at which the torque converter clutch will lock. This should usually be toward the lower end
of the 4th gear operating range.
3.3.5
Torque Converter Clutch Unlock Speed
ULK SPD
This is the speed at which the torque converter clutch will automatically unlock if previously locked. This gives
some buffer room after the lock occurs (based on the Torque Converter Clutch Lock Speed).
Adjusting this parameter properly can help prevent a "hunting" or cycling situation where the TCC turns on and off.
In most circumstances, this parameter will be set to a speed below the minimum 4th gear speed and thus won't be
used because the 4-3 shift will always unlock the TCC.
3.3.6
Torque Converter Clutch Lock Delay
LK DLY
This parameter adjusts how long after a 3-4 shift until the torque converter clutch will be allowed to lock.
After the transmission shifts into 4th gear, a timer countdown begins. Once the timer reaches zero, the clutch can
lock, subject to the other parameter settings.
The main function of this parameter is to prevent a 3-4 shift from being immediately followed by a torque converter
clutch lock. Depending on the vehicle, and especially the torque converter stall speed, this rapid sequence of shift
and lock events can be unpleasant.
3.4 Torque Converter Clutch Parameters (Chrysler)
3.4.1 Introduction
The torque converter is hydraulic coupling that trades slippage for torque multiplication, effectively providing an
additional spread of gear ratios for drive-off, acceleration, and passing.
The torque converter clutch locks all of the elements of the torque converter together, preventing slippage and
losses in the torque converter when isn't needed.
This improves fuel economy, reduces engine speed, and builds less heat in the transmission.
Here are the basic rules used for controlling the torque converter clutch or "TCC":
The most important considerations for deciding when to lock and unlock the TCC are vehicle speed and
engine load / throttle.
At lower speeds and higher loads, the torque converter should be active, so the clutch should be unlocked to
allow torque multiplication.