Figure 14. Pushbutton Shift Selectors

WTEC III ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL

GENERAL DESCRIPTION

D N R

MODE ID

DNR

MODE

MODE INDICATOR (LED)

PUSHBUTTON

STRIP PUSHBUTTON

ELECTOR

HIFT SELECTORS

V03356

Figure 14. Pushbutton Shift Selectors

14.

SPEED SENSORS (Figure 15)

Three speed sensors -- engine speed, turbine speed, and output speed -- provide information to the ECU. The

engine speed signal is generated by ribs on the shell of the torque converter pump. The turbine speed signal is

generated by the rotating-clutch housing spline contours. The output speed signal is generated by a toothed

member attached to the output shaft (except for the MD 3070, where the toothed member is the transfer case idler

gear). The speed ratios between the various speed sensors allow the ECU to determine if the transmission is in the

selected range. Speed sensor information is also used to control the timing of clutch apply pressures, resulting in

the smoothest shifts possible. Hydraulic problems are detected by comparing the speed sensor information for the

current range to that range's speed sensor information stored in the ECU memory.

ENGINE

HD/B 500

MD/B 300/B 400

MD 3070 PT

OUTPUT

(EXTERNAL)

TURBINE

RETARDER OUTPUT

OUTPUT

(EXTERNAL)

(INTERNAL)

(EXTERNAL)

(INTERNAL)

V03470

Figure 15. Speed Sensors