A Twist of Fate
Aisin Seiki’s six-speed transmission used in medium-duty trucks is called by various names. It is the AS68RC in Dodge incomplete-chassis packages using L6 6.7-liter diesel engines. It is also called the AS6 in the Mitsubishi Fuso, the M036A6 in Nissan UDs and the A465 in Isuzu NPR trucks.
One of the common failures with this transmission is the stator turning in the pump (figures 1 and 2). A similar problem occurs with Allison 1000/2000 transmissions, in which it causes a TCC overheat and/or C1-clutch failure. You can quickly determine this by pulling the return cooling line. Oil comes out of the case fitting instead of the cooling line.