Swap shift control

An automatic transmission for a vehicle comprising:

• a main box housing a first plurality of gears;
• an under drive assembly housing a second plurality of gears, said under drive assembly in mechanical communication with said main box;
• a series of engagement elements operable between an engaged position and a disengaged position, said series of engagement elements including an overrunning engagement element in mechanical communication with said second plurality of gears;
• and
• a controller operable to selectively toggle said series of engagement elements between said engaged position and said disengaged position to selectively couple one of said first plurality of gears and one of said second plurality of gears to said input shaft and said output shaft;
• wherein said controller is operable to disengage said overrunning engagement element from engagement with one of said second plurality of gears within a range of about 40 to 70 milliseconds after said main box begins to slip.

A method for controlling operation of an automatic transmission of a vehicle comprising:

• applying a first engagement element to select a gear from a first plurality of gears in a transmission to achieve a desired output speed of said first plurality of gears in response to driver acceleration of the vehicle;
• transmitting said output speed of said first plurality of gears to a second plurality of gears;
• applying an engagement element to select a first gear from said second plurality of gears in response to said driver acceleration to achieve a desired output speed of said second plurality of gears and a first gear ratio of said transmission;
• releasing said first engagement element and applying a second engagement element to select a second gear from said first plurality of gears to achieve an output speed change of said first plurality of gears in response to further acceleration of the vehicle;
• transmitting said output speed change from said first plurality of gears to a second plurality of gears;
• and
• releasing said engagement element from said first gear of said second plurality of gears within a range of about 20 to 120 milliseconds after said output speed change of said first plurality of gears to accomplish an output speed change of said second plurality of gears and achieve a second gear ratio of the transmission.