General description
1. In the torque converter clutch (TSS) automatic transmission uses a single valve controlled by a solenoid (on engines 3.1 l) or two solenoids (on 3.8 l engines), providing rigid mechanical engagement of the engine flywheel with the output shaft of the gearbox through the torque converter. As a result, due to the elimination of slippage in the torque converter, engine speed is reduced, and thus the level of harmful emissions. This also results in lower fuel consumption.
Note. On 1992 vehicles equipped with front and rear air conditioning systems, the TCC system locks up at speeds in the order of 25 mph (40 km/h). On vehicles equipped with only the front air conditioning system, the TCC system operates at two different speeds. With A/C on, lockup occurs at 35 mph (56 km/h), and when off - at a speed of 25 miles per hour (40 km/h). Compressors of different models are installed in these air conditioning systems.
2. In order for the torque converter clutch to work properly, two conditions must be met:
- A) The engine must warm up before engaging the clutch. Engine coolant temperature sensor (see section 4) tells the ECM/PCM when the engine has reached normal operating temperature.
- b) In order for the pressure of the working fluid to rise to the level necessary to actuate the valve, the vehicle must reach the minimum required speed. If the hydraulic pressure has reached the desired value, the ECM/PCM supplies the solenoid (solenoids) signal to turn on the torque converter clutch.
3. After the clutch is engaged, the ECM/PCM uses the information from the TPS sensor to disengage the lock when the vehicle accelerates or decelerates at a certain degree of acceleration (slowdown).
4. The torque converter clutch assembly also uses a brake switch that, when the brake pedal is depressed, cuts off the power circuit to the TCC solenoid.
5. On the gearbox model ZT40 (engine 3.1 l) The TCC system uses the 3rd gear switch to signal the ECM which gear is in the transmission. The ECM uses this data to change the conditions under which the clutch will engage and disengage. However, it is not necessary for the ECM to engage the clutch in a higher gear. Transmissions that use gear select switches can be identified by three wires coming out of the TCC electrical connector.
6. On the gearbox model 4T60-E (engine 3.8 l) the clutch engagement solenoids control the amount of fluid that enters the TCC system.
7. In addition, on the 4T60-E transmission, the TCC system uses a solenoid controlled by pulse time locks to change the amount of hydraulic pressure in order to make the TCC system shift more smoothly and with less noise (PWM) the signal it receives.
Examination
8. With the torque converter clutch engaged all the time, the engine stalls immediately, just as it does with engines equipped with a manual shift transmission.
9. If the torque converter clutch is not engaged, fuel economy may not be as expected. If the vehicle speed sensor malfunctions (VSS) (see section 4) TSS system will not work.
10. A TCC-equipped transmission has different performance characteristics than an automatic transmission without TCC. If shots are heard in the muffler or the vehicle jerks, perform the following check.
11. Install a tachometer.
12. After warming up the engine while driving to normal operating temperature, keep the vehicle speed at 50-55 mph.
13. Lightly depressing the brake pedal, you should feel a slight kick back indicating that the TCC system is disengaging. In this case, the engine speed should increase slightly.
14. When the brake pedal is released, the torque converter clutch will reengage and the engine speed will drop slightly.
15. If the TCC system is not working satisfactorily, send the vehicle for a system check.