Torque Converter
The converter consists of the impeller, the turbine wheel, the reaction member (stator) and the oil to transmit torque. The impeller, which is driven by the engine, causes the oil in the converter to flow in a circular pattern. This oil flow meets the turbine wheel, where is direction of flow is deflected. At the hub, the oil leaves the turbine and reaches the reaction member (stator), where it is once again deflected so that it reaches the impeller at the correct angle of flow.
The reversal effect generates movement in the stator, the reaction torque then amplifies the turbine torque.
The ratio between turbine torque and torque is referred to as torque multiplication.
The greater the difference is speed between the pump and turbine, the greater the torque multiplication; it is at its highest when the turbine is at a standstill. The higher the speed of the turbine, the lower the torque multiplication.
When the turbine speed reaches about 85% of the pump speed, torque multiplication = 1, i.e. the turbine torque equivalent to pump torque.
Scheme 1
The stator, which bears against the housing via the freewheel, is then rotating freely in the oil flow and the freewheel is over-come. From this point onwards, the converter acts as a straightforward fluid coupling.
Torque Converter Lock-up Clutch (TCC)
The converter lock-up clutch is a device, which eliminates converter slip and thus helps to improve fuel consumption.
The previous control principle for converter lock-up clutch operation has been replaced by a controlling function on the 4 HP 16. The converter lock-up clutch is engaged and released in a controlled manner. During the controlled phase, a slight speed difference between the impeller and turbine wheel is established. This ensures that the engine's rotating vibration is not phased on to the transaxle. The result is optimum shift quality.
An electronic pressure-regulating valve determines pressure regulation of the lock-up converter clutch's piston. When open (conversion range), the oil pressure behind the converter lock-up clutch piston and in the turbine zone is equal. The direction of flow is through the turbine shaft and through the space behind the piston, to the turbine chamber.
Scheme 2
To engage the lock-up clutch, the direction of flow is modified (reversed) via a valve in the hydraulic selector unit. At the same time, the space behind the lock-up clutch piston is vented. The oil pressure passes from the turbine chamber to the lock-up clutch piston and presses it against the converter's cover. The turbine is thus blocked by way of the linings between the piston and cover, and permits rigid through drive with no slip (or reduced slip if controlled) to the mechanical stage of the transaxle.
Scheme 3
Torque Converter Lock-Up Clutch (TCC) Diagnosis
To properly diagnosis the lock-up clutch (TCC) system, perform all electrical testing first and then the hydraulic testing.
The TCC is applied by fluid pressure which is controlled by a solenoid Located inside the valve body. The solenoid is energized by completing an electrical circuit through a combination of switches and sensors.
Torque Converter Stator
The torque converter stator roller clutch can have one of 2 different type malfunctions
- Stator assembly freewheels in both directions.
- Stator assembly remains Locked up at all times.
General Specifications
| Definition | |
|---|---|
| Transaxle Type | 4-speed with 4-wheel drive and transverse engine |
| Input Torque | 240 N.m (177 lb-ft) |
| Transaxle Weight | 76 kg (168 lb) |
| Transaxle Fluid Type (manufacture company) | ESSO LT 71141 or TOTAL ATF H50235 |
| Transaxle Fluid Capacity | 7.8 ± 0.2 qt (7.4 ± 0.2 L) |
GENERAL SPECIFICATIONS
Fluid Capacity
| L | Qt | |
|---|---|---|
| Bottom Pan Removal | 4 | 4.2 |
| Complete Overhaul | 7.4 ± 0.2 | 7.8 ± 0.2 |
| Torque Converter Removal | 2 | 2.1 |
| (Measurements are approximate) | ||
FLUID CAPACITY SPECIFICATION
Tightening Torque Specifications
| Application | N.m | Lb-in. |
|---|---|---|
| Bearing Plate Bolts | 23.5 | |
| Slotted Nut | 220 | |
| Rear Cover Attachment Bolts | 23.5 | |
| Baffle Plate Attachment Bolts | 10 | 89 |
| Park/Neutral Position Switch | 10 | 89 |
| Fluid Pump Connecting Bolts | 10 | 89 |
| Fluid Filter Housing Cover Attachment Bolts | 10 | 89 |
| Input Speed sensor Attachment Bolts | 8 | 71 |
| Output Speed Sensor Attachment Bolts | 8 | 71 |
| Valve Body Bolts | 8 | 71 |
| Valve Body Upper & Lower Fixing Bolts | 6 | 53 |
| Fluid Pan Connecting Bolts | 6 | 53 |
| Fluid Pan Drain Plug | 45 | |
| Fluid Level Plug | 45 | |
| Line Pressure Plugs | 20 | |
| Valve Housing 1 Cover Attachment Bolts | 6 | 53 |
| Solenoid Valve Attachment Bolts | 6 | 53 |
| Pressure Control Regulator (EDS) Attachment Bolts | 6 | 53 |
| Oil Cooler Inlet Pipe Bolts | 35 | |
| Oil Cooler Outlet Pipe Bolts | 35 | |
| Shift Control Cable Adjuster Pinch Nut | 8 | 71 |
| Shift Control Cable Attachment Nut | 8 | 71 |
| Upper Transaxle-to-Engine Bolts | 73 | |
| Selector Lever (On Transaxle Case) | 15 | |
| TCM Mounting Nuts | 23 | |
| Torque Converter Attachment Bolts | 45 | |
| Shift Control Assembly Mounting Bolt | 8 | 71 |
| Left Transaxle Mounting Bracket Bolts | 40 | |
| Left Transaxle Mounting Bracket Cage Bolt and Nut | 65 | |
| Left Lower Engine-to-Transaxle Mounting Bolts | 73 | |
| Right Lower Engine-to-Transaxle Mounting Bolts | 73 | |
| Oil Pan Flange-to-Transaxle Bolts | 31 | |
| Rear Transaxle Mounting Bracket Bolts | 65 |
TIGHTENING TORQUE SPECIFICATIONS