Automatic Transmission Description

Automatic Transmission Description
^ This automatic transmission is a full automatic type with 4-speed plus overdrive (O/D). The torque converter is a 3-element, 1-step and 2-phase type and is equipped with an electronically controlled lock-up mechanism. The gear shift device consists of 3 sets of planetary gear units, 3 disc type clutches, 4 disc type brakes and 3 one-way clutches. The gear shift is done by selecting one of 7 positions (P, R, N, D, 4, 3 and L) by means of the select lever installed on the floor.
^ This automatic transmission has the clutch-to-clutch (brake) control function when the gear is upshifted from the 4th gear to the 5th gear and downshifted from the 5th gear to the 4th gear. With this function, gears are synchronized by controlling the hydraulic pressure to the forward clutch and No.1 brake without using the one-way clutch. This automatic transmission also has the line pressure learning control function to achieve gear changes smoothly. Therefore, when any of the following conditions applies, initialize the line pressure learning control of TCM. Neglecting this initialization may cause excessive shift shock.
^ The A/T unit has been overhauled
^ The A/T unit has been replaced
^ The engine has been overhauled
^ The engine has been replaced
^ TCM has been replaced with used one
^ TCC slip control even at a lower speed than when the TCC gets engaged completely, control over the TCC pressure control solenoid works to cause the TCC to slip (be engaged slightly), thereby improving the transmission efficiency. While such slip control is being executed, the oil pressure applied to the TCC is controlled by the TCC pressure control solenoid so that the difference between the engine speed and the input shaft speed becomes close to the specified value.
Also, during deceleration, the TCC is made to slip (be engaged slightly) to raise the engine speed and enlarge the fuel cut operation range so that better fuel consumption is achieved.
Due to this reason, it is absolutely necessary for the automatic transmission to use ATF suitable for slip control. Use of any fluid other than the specified ATF may cause juddering or some other faulty condition to occur.