GENERAL DESCRIPTION - TM-9-2320-303-24-10189

WTEC III ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL

GENERAL DESCRIPTION

15.

CONTROL MODULE (Figure 16)

The WT Series transmission control module contains a channel plate on which is mounted: the main valve body

assembly, the stationary-clutch valve body assembly, and the rotating-clutch valve body assembly. For valve

locations, refer to SIL 27-WT-93, Rev. A. Pulse width modulated solenoids are used in the valve bodies. The

rotating-clutch valve body assembly contains A (C1), B (C2), and F (lockup) solenoids, solenoid regulator valves

controlled by the solenoids, and the C3 pressure switch. The stationary-clutch valve body assembly contains

C (C3), D (C4), and E (C5) solenoids and solenoid regulator valves controlled by the solenoids and the

C3 accumulator relay valve. The main valve body assembly contains G solenoid and the C1 and C2 latch valves

controlled by the solenoid, the main and lube regulator valves, the control main and converter regulator valves, and

the converter flow valve and exhaust backfill valves. The low valve body assembly (MD 3070PT and HD 4070)

contains N and J solenoids.

MD/B 300/B 400 CONTROL MODULE

MD 3070 CONTROL MODULE

HD/B 500 CONTROL MODULE

V03354

Figure 16. WTEC III Control Module

A temperature sensor (thermistor) is located in the internal wiring harness. Changes in sump fluid temperature are

indicated by changes in sensor resistance which changes the signal sent to the ECU (see chart in Section 5,

Code 24).

The oil level sensor is a float type device, mounted on the control module channel plate, which senses transmission

fluid level by electronically measuring the buoyancy forces on the float. The sensor operates on 5 VDC supplied by

the ECU. The oil level sensor is required on all models with a shallow sump but is optional on other models. The

oil level sensor is not available on the MD 3070.

The C3 pressure switch is mounted on the rotating-clutch valve body assembly and indicates when pressure exists

in the C3 clutch-apply passage. An accumulator/relay valve is in-line ahead of the C3 pressure switch and prevents

high frequency hydraulic pulses generated by the C3 solenoid from cycling the C3 pressure switch.

Also mounted in the control module is the turbine speed sensor for the MD/B 300/B 400 models. The turbine speed

sensor is directed at the rotating-clutch housing. (The turbine speed sensor on the HD/B 500 models is located on

the outside of the main housing.)