A method for controlling a coasting downshift in an automatic transmission
having a torque converter that includes an impeller driveably connected
to an engine and a turbine hydrokinetically coupled to the impeller and
driveably connected to the transmission input. During a coast condition,
the speed of the turbine decreases, and the speed of the engine decreases
to and is maintained at an engine idle speed. After the downshift event
begins, the turbine speed increases due a transfer of torque from an
off-going transmission control element to an oncoming control element.
Engine speed increases steadily until it reaches the target engine speed.
The downshift is completed, and engine speed decreases until it again
reaches the idle speed.