- Power Train Electronic Control Module
- Torque Converter
- Transmission Planetary and Transmission
The three basic systems have a hydraulic connection, an electrical connection, a magnetic connection, or a mechanical connection. Power is supplied from the engine to the torque converter and then goes to the transmission. If the transmission is in gear, power flows from the transmission to the output shaft. The operation of the power train begins at the power train Electronic Control Module (ECM). The power train ECM receives information about the selected speed of operation through the shifter in the electrical system. The power train ECM uses information from several sensors in the electrical system to control the torque converter and the transmission hydraulic system by energizing the appropriate solenoids.
The rotating housing of the torque converter is fastened directly to the engine flywheel. The torque converter has a lockup clutch for direct drive and a one-way clutch for torque converter drive. During torque converter drive, power is transmitted through the torque converter hydraulically to the transmission. During direct drive, there is a direct connection between the engine flywheel and the transmission.
The power train ECM will hydraulically activate the lockup clutch solenoid for direct drive operation. The full power from the engine flywheel is transmitted through the torque converter when the torque converter is in direct drive. The lockup clutch becomes a direct connection between the rotating housing and the output shaft of the torque converter. The output shaft of the torque converter is connected to the planetary. The power train ECM will activate the appropriate electronic clutch pressure control (ECPC) valves to activate the correct transmission clutches when shifts are needed. The transmission clutches mechanically connect the transmission input shaft to the output shaft. Different combinations of clutches result in different gears and transmission output shaft speeds, as shown in Table 1.
| CX38-P892 Transmission Clutch Assignments | |||||||||
|---|---|---|---|---|---|---|---|---|---|
| Operation | Gear Ratios | CLUTCHES | Transmission Output Speed at 800 RPM Input with LUC Engaged (RPM) | Transmission Output Speed at 2200 RPM Input with LUC Engaged (RPM) | |||||
| 1 | 2 | 3 | 4 | 5 | 6 | ||||
| Park | O | O | O | − | − | ||||
| Neutral 1 | O | O | − | − | |||||
| Neutral 2 | O | O | − | − | |||||
| 1 Forward | 6.210 | O | O | O | 140 | 384 | |||
| 2 Forward | 4.696 | O | O | O | 224 | 616 | |||
| 3 Forward | 3.384 | O | O | O | 294 | 809 | |||
| 4 Forward | 2.689 | O | O | O | 411 | 1129 | |||
| 5 Forward | 2.033 | O | O | O | 560 | 1540 | |||
| 6 Forward | 1.667 | O | O | O | 800 | 2200 | |||
| 7 Forward | 1.205 | O | O | O | 1088 | 2992 | |||
| 8 Forward | 1.000 | O | O | O | 1267 | 3485 | |||
| 9 Forward | 0.693 | O | O | O | |||||
| 1 Reverse | —5.915 | O | O | O | 179 | 493 | |||
| 2 Reverse | -2.561 | O | O | O | |||||
When the output shaft of the transmission is rotating, the speed sensors send an AC frequency signal (HZ) that matches the number of gear teeth passing the sensor per second to the ECM. The ECM compares the frequency from the speed sensor (HZ) to the number of pulses per revolution in order to determine the speed of the rotating components. The ECM uses the input from the speed sensors in order to regulate transmission shifts.
The CX35-P892 transmission has eight forward gears. The ECM will engage the desired gear and speed depending on the gear selected by the operator and transmission ECM programming, which is dependent on operating mode, load factors, output speed of the torque converter and output speed of the transmission. The torque converter will be in torque converter drive for a short time during transmission shifts. This provides smoother engagement of the transmission clutches.
The torque converter hydraulic system uses oil that is also common with the transmission hydraulic system. These systems use the same section of the transmission case. Some of the components in the torque converter hydraulic system include a torque converter inlet relief valve, a torque converter outlet relief valve, a gear pump, and a torque converter lockup clutch. Pressurized oil that will engage the lockup clutch comes from the gear pump. Oil flows from the gear pump, through the transmission oil filter. Some of the oil will then be sent to the torque converter lockup clutch. When the ECM signals the torque converter lockup clutch solenoid, oil will flow through the solenoid and engage the torque converter lockup clutch.
Oil from the transmission oil filter also flows to the torque converter inlet relief valve and into the torque converter. Oil exits the torque converter and flows through the torque converter outlet relief valve. Oil from the outlet relief valve goes through the cooler and then is used to lubricate the transmission. Components of the transmission hydraulic system include a transmission hydraulic control, a transmission gear pump, a hydraulic filter of the transmission, a transmission magnetic screen, and a transmission oil cooler. The transmission gear pump sends oil through the hydraulic filter of the transmission and then to the transmission hydraulic control. The basic components of the transmission hydraulic control are the ECPC valves. This oil also supplies the lockup clutch solenoid. The solenoids connect the electrical systems and the hydraulic systems.