The 4EAT Electronically Controlled Automatic Transaxle is installed in the Probe. It features a combination of electronic and mechanical systems for controlling forward gear shifting and torque converter lockup, for quietness and economy. A manual switch is provided to allow the transaxle to be manually shifted while driving on steep, slippery, or dangerous roads.
The 4EAT has a single compact combination-type planetary gear with 4-speed capability. It also features a variable-capacity oil pump which provides a constant oil quantity at and above a medium speed, and reduces the power losses resulting from pumping more oil than necessary at higher speeds.
The electronic system controls the transmission shifting in forward speeds and torque converter lockup by means of solenoid operated valves. When energized, the solenoid valves actuate the clutches and bands to control shifting in the planetary gear. Shift timing and lockup are regulated by the 4EAT control unit in programmed logic and in response to various input sensors and switches.