Automatic Transmission: Maintenance Suzuki Forenza I

Fluid Pump

The fluid pump is located between the torque converter and the transaxle case and is driven directly by the torque converter. The pump sucks the fluid through a filter and delivers it to the main pressure regulator valve of the control system. Excess fluid flows back to the pump. The fluid pump fulfills the following functions

1. Generates line pressure.
2. Delivers fluid under pressure to the torque converter, thus preventing air bubbles in the fluid.
3. Induces a flow of fluid through the torque converter in order to eliminate heat.
4. Supplies fluid pressure to the hydraulic control system.
5. Supplies fluid pressure to the shift components.
6. Lubricates the transaxle with fluid.

Scheme 90

Transaxle Fluid Temperature (TFT) Sensor

The TFT sensor is a positive temperature coefficient thermistor (temperature sensitive resistor) that provides information to the TCM regarding transaxle fluid temperature. The temperature sensor is located in valve body. Calculated temperature is a factor used to determine the shift time and shift delay time.

The internal electrical resistance of the sensor varies in relation to the operating temperature of the transaxle fluid (see chart).

Scheme 91

The TCM sends a 5 volt reference signal to the temperature sensor and measures the voltage rise in the electrical circuit. A higher fluid temperature creates a higher resistance in the temperature sensor, thereby measuring a lower voltage signal.

Scheme 92

The TCM measures this voltage as another input to help control line pressure, shift schedules and TCC apply. When transaxle fluid temperature reaches 140 °C (284 °F) the TCM enters "hot mode." Above this temperature the TCM modifies transaxle shift schedules and TCC apply in an attempt to reduce fluid temperature by reducing transaxle heat generation. During hot mode the TCM applies the TCC at all times in fourth gear.

Also, the TCM commands the 2 - 3 and 3 - 4 shifts earlier to help reduce fluid heat generation. Hot mode may not be available on some applications.

RESISTANCE REFERENCE CHART

1. Provides transaxle fluid temperature information to the TCM for determining alternate shift patterns and TCC apply during high temperature conditions (hot mode operation).
2. An incorrect transaxle temperature sensor input could causes altered shift patterns, poor shift quality and incorrect TCC apply.

Scheme 93

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Scheme 98

In Park or Neutral with the engine running there is no drive to the planetary gear set. Line pressure (from the oil pump) is supplied to the valve body. Only clutch B is supplied and the torque converter is released.

Lubrication/Cooling

The lubricating valve ensures that the converter is supplied with cooling oil first if the pump rate is low. The lubricating pressure valve in addition guarantees that the necessary amount of cooling and lubricating oil is available via the bypass duct.

The fluid, which is supplied from the torque converter, flows to the cooler via the lubrication valve.

Scheme 99

In Reverse, transaxle drive is via the input shaft and clutch B. The elements of this transaxle function are as follows

1. Clutch B is engaged and drives the reverse sun gear in a clockwise direction.
2. The D band is engaged and holds the planetary gear carrier (front & rear) stationary causing the differential pinion to rotate clockwise.
3. The differential rotates in a counterclockwise direction.
4. The output shaft is driven in a counterclockwise or reverse direction.

The lubricating valve ensures that the converter is supplied with cooling oil first if the pump rate is low. The lubricating pressure valve in addition guarantees that the necessary amount of cooling and lubricating oil is available via the bypass duct.

The fluid, which is supplied from the torque converter, flows to the cooler via the lubrication valve.

Scheme 100

In Drive 1, transaxle drive is via the input shaft to clutch B. The elements of this transaxle function are as follows

1. Clutch B is engaged to drive the rear sun gear.
2. The rear sun gear drives the front planetary gear carrier clockwise.
3. The rear planetary gear carrier drives the front ring gear and front planetary gear carrier clockwise.

The lubricating valve ensures that the converter is supplied with cooling oil first if the pump rate is low. The lubricating pressure valve in addition guarantees that the necessary amount of cooling and lubricating oil is available via the bypass duct.

The fluid, which is supplied from the torque converter, flows to the cooler via the lubrication valve.

Scheme 101

In Drive 2, the transaxle drive is via the input shaft and clutch E. The elements of this transaxle function are as follows

1. Clutch E is applied to drive the front ring gear.
2. The front ring gear drives the front planetary gear carrier.
3. The front planetary gear carrier drives the differential pinion gear clockwise.
4. Brake F is applied holding the front sun gear stationary.

The lubricating valve ensures that the converter is supplied with cooling oil first if the pump rate is low. The lubricating pressure valve in addition guarantees that the necessary amount of cooling and lubricating oil is available via the bypass duct.

The fluid, which is supplied from the torque converter, flows to the cooler via the lubrication valve.

Scheme 102

In Drive 3, transaxle drive is via the input shaft to clutches B and E. The elements of this transaxle function are as follows

1. Clutches B and E are engaged to drive the rear sun gear and rear planetary gear carrier clockwise.
2. The clockwise rotation of the rear sun gear and rear planetary gear carrier will cause the front planetary gear to rotate in the same direction.

Transaxle Fluid Level Service

This procedure is to be used when checking a concern with the fluid level in a vehicle. A low fluid level will result in slipping and loss of drive/reverse or delay on engagement of drive/reverse when the vehicle is cold. The vehicle is first checked for transaxle diagnostic messages on the scan tool. If the oil level is low, it is possible to register a vehicle speed signal fault.

The vehicle is to be test driven to determine if there is an abnormal delay when selecting drive or reverse, or loss of drive. One symptom of low fluid level is a momentary loss of drive when driving the vehicle around a corner. Also when the transaxle fluid level is low, a loss of drive may occur when the transaxle fluid temperature is low.

When adding or changing transaxle fluid use ESSO LT 71141 or TOTAL ATF H50235 automatic transaxle fluid or other approved fluids. The use of incorrect fluid will cause the performance and durability of the transaxle to be severely degraded.

Fluid Level Set after Service

1. Depending on the service procedure performed, add the following amounts of fluid through the filler plug hole prior to adjusting the fluid level: Oil pan removal - 4 liters (4.23 quarts) Converter removal - 2 liters (2.11 quarts) Overhaul - 6.9 ± 0.2 liters (7.3 ± 0.2 quarts) Oil drain plug removal - 4 liters (4.23 quarts)
2. Follow steps 1 through 4 of the Fluid Level Diagnosis Procedure.
3. Clean all dirt from around the fluid filler plug. Remove the fluid filler plug. Clean the filler plug and check that there is no damage to the "O" ring.
4. Lower the vehicle with the filler plug still removed and start the vehicle in P (Park) with the parking brake and the brake applied. With the engine idling, move the gear shift lever through the gear ranges, pausing a few seconds in each range and adding the fluid until gear application is felt. Then add an additional 0.5 liters of fluid. Return the gear shift lever to P (Park). Turn the engine OFF and raise the vehicle. Install the fluid filler plug and tighten it to 45 N.m (34 lb-ft).
5. Drive the vehicle at 3.5 - 4.5 km (2.2 - 2.8 miles) with light throttle so that the engine does not exceed 2,500 RPM. This should result in the transaxle temperature being in the range 20 - 45 °C (68 - 113 °F). With the brake applied, move the shift lever through the gear ranges, pausing a few seconds in each range at the engine idling.
6. Return the gear shift lever to P (Park). Turn the engine OFF and raise the vehicle on the hoist, if applicable, ensuring the vehicle is level. When the three minutes passed after the engine stopped, remove the filler plug. Check if the fluid level is aligned with the bottom of the filler hole. If not, add a small quantity of fluid to the correct level. Install the fluid filler plug and tighten it to 45 N.m (34 lb-ft).
7. Wipe any fluid around the filler plug with a rag or shop towel.

Repairing the Fluid Leak

Once the leak point is found the source of the leak must be determined. The following list describes the potential causes for the leak

1. Fasteners are not torqued to specification.
2. Fastener threads and fastener holes are dirty or corroded.
3. Gaskets, seals or sleeves are misarranged, damaged or worn.
4. Damaged, warped or scratched seal bore or gasket surface.
5. Loose or worn bearing causing excess seal or sleeve wears.
6. Case or component porosity.
7. Fluid level is too high.
8. Plugged vent or damaged vent tube.
9. Water or coolant in fluid.
10. Fluid drain back holes plugged.

Transaxle Fluid Level Checking Procedure

Tools Required

DW260-070 Transaxle Fluid Plug Remover/Installer

Scheme 103

Scheme 104

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Scheme 106

1. Start the engine and allow the engine to idle for approximately 5 minutes, or, if possible, drive the vehicle for a few kilometers (miles) to warm the transaxle fluid. Check the fluid level when the transaxle is over 30 °C (86 °F).
2. Press the brake pedal and move the shift lever through the gear ranges, pausing a few seconds in each range. Return the shift lever to the park position. (Left-Hand Drive Shown, Right-Hand Drive Similar.)
3. Raise and suitably support the vehicle.
4. Place a fluid container below the fluid level plug.
5. Remove the fluid level plug using the plug remover/installer DW260-070. Because the transaxle operates correctly over a range of levels, fluid may or may not drain out of the plug hole when the plug is removed.
6. Check the oil fluid level. If fluid does not drain through the plug hole after adding a total of 4 liters, then the transaxle was either underfilled or the transaxle is leaking fluid. Inspect the transaxle for fluid leaks. Fix any leaks before setting the transaxle fluid level.
7. Install the fluid level plug using the plug remover/installer DW260-070. Tighten: Tighten the Fluid Level Plug to 45 N.m (33 lb-ft).
8. When the fluid level checking procedure is completed, wipe any fluid from the transaxle case with a rag or shop towel. Also, check that the fluid fill cap and the vent tube are properly installed.

Changing the Fluid

Tools Required

DW260-070 Plug Remover/Installer

Scheme 107

1. Disconnect the negative battery cable.
2. Raise and suitably support the vehicle.
3. Place a fluid container below the fluid drain plug.
4. Remove the transaxle fluid drain plug using the plug remover/installer DW260-070.
5. Adding transaxle fluid. Refer to «Transaxle Fluid Level Checking Procedure»(ref-257093-S35556437662007062900000) .
6. Install the transaxle fluid drain plug using the plug remover/installer DW260-070. Tighten: Tighten the Transaxle Fluid Drain Plug to 45 N.m (33 lb-ft).
7. Connect the negative battery cable.

1. Add transaxle fluid through the fill cap hole prior to adjusting the fluid level. The amount of fluid to add should be based on the type of service done. Adjustment Notice Use ESSO LT 71141 or TOTAL ATF H50235 transaxle fluid only. Oil pan removed: 4 L (4.2 qt) Torque converter removed: 2 L (2.1 qt) Complete overhaul: 6.9 ± 0.2 L (7.3 ± 0.2 qt) Drain plug removed: 4 L (4.2 qt)
2. Check the transaxle fluid level. Refer to «Transaxle Fluid Level Checking Procedure»(ref-257093-S35556437662007062900000) .
3. Add additional fluid through the fill cap hole in 0.5 L (0.5 qt) increments until the fluid comes out through the plug hole.
4. Allow the fluid to finish draining out through the plug hole, then install the fluid level plug.
5. When the fluid level setting procedure is completed, wipe any fluid from the transaxle case with a rag or shop towel. Also, check that the fluid fill cap and the vent tube are properly installed.

The following are potential causes for fluid leaks. Check and repair, as necessary.

1. Fasteners are not tightened to specifications.
2. Fastener threads and tapped holes are dirty or corroded.
3. Gaskets, seals or sleeves are misaligned, damaged, or warped, or scratched.
4. The manual shaft is nicked or damaged.
5. There is a loose or worn bearing causing excess seal or sleeve wear.
6. Case or component porosity.
7. The fluid level is too high.
8. There is a plugged vent or a damaged vent tube.
9. There is water or coolant in the fluid.
10. Fluid drain back holes are plugged.