Automatic Transmission: Specifications Saab 9-5 II

Transmission Fluid Temperature Sensor Specifications

Fastener Tightening Specifications

Transmission General Specifications

Torque Converter Components

Note. The car must not be stalled (car held with brakes and full throttle in D position) for longer than 5 seconds.

The torque converter is bolted to the engine flywheel (flexplate). The converter is filled with oil via pressure from the automatic transmission oil pump. This is itself a hydraulic transmission that amplifies the engine torque the more it slips. The greatest torque amplification is obtained when the engine stalls (car stationary and full throttle in Drive), as the engine torque is at a maximum while the transmission input shaft is stationary. There will not be any amplification if the engine speed is the same as the transmission input shaft speed.

The torque converter clutch (lock up) is activated at a steady speed when there is no need for torque amplification. The difference in speed between the engine and the transmission does give an amplification of torque even at steady speeds but also entails heat loss. These losses result in unnecessary fuel consumption.

Scheme 1

1. Torque Converter
2. Transmission's output gear
3. Intermediate Shaft
4. Differential

1. (b1) Brake
2. (b2) Brake
3. (c1) Clutch
4. (c2) Clutch
5. (c3) Clutch
6. (f1) Free wheel

The transmission has 2 planetary gear units; front and rear. The front one is a single planetary gear and the rear one is double. The rear unit is Ravigneaux type with two planet gears between the rear sun gear and the only ring gear, which is the transmission output shaft. The two planet gears are fitted on a common planet carrier.

The front planetary gear sun gear is fixed and the power from the torque converter enters via its ring gear. This entails a reduction of the planet carrier speed used for gear 1-5 and R. The power from the planet carrier is conveyed to the rear planetary gear unit via clutches C1 and C3.

The rear planetary gear unit receives power either directly from the torque converter via clutch C2 or from the front planetary gear via clutches C1 and C3. The 2 brakes, B1 and B2, are used to hold firm the components in the rear planetary gear unit. B2 is combined with a free wheel (F1).

The activation of one or more friction elements results in a gear ratio. Brakes and clutches are activated hydraulically using solenoids controlled by the transmission control module (TCM).

The table shows the active elements for each of the gears.

Torque Converter Diagnosis

The torque converter clutch (TCC) is applied by fluid pressure, which is controlled by a pulse width modulated (PWM) solenoid valve. This solenoid valve is located inside of the automatic transmission assembly. The solenoid valve is controlled through a combination of computer controlled switches and sensors.

Torque Converter Stator

The torque converter stator roller clutch can have two different malfunctions.

1. The stator assembly freewheels in both directions.
2. The stator assembly remains locked up at all times.

Torque Converter Clutch Shudder

The key to diagnosing TCC shudder is to note when it happens and under what conditions.

TCC shudder which is caused by the transmission should only occur during the apply or the release of the converter clutch. Shudder should never occur after the TCC plate is fully applied.

If the shudder occurs while the TCC is applying, the problem can be within the transmission or the torque converter. Something is causing one of the following conditions to occur

1. Something is not allowing the clutch to become fully engaged.
2. Something is not allowing the clutch to release.
3. The clutch is releasing and applying at the same time.

One of the following conditions may be causing the problem to occur

1. Leaking turbine shaft seals
2. A restricted release orifice
3. A distorted clutch or housing surface due to long converter bolts
4. Defective friction material on the TCC plate

Torque Converter Evaluation and Diagnosis

Replace the torque converter if any of the following conditions exist

1. External leaks appear in the hub weld area.
2. The converter hub is scored or damaged.
3. The converter pilot is broken, damaged, or fits poorly into the crankshaft.
4. You discover steel particles after flushing the cooler and the cooler lines.
5. The pump is damaged, or you discover steel particles in the converter.
6. The vehicle has TCC shudder and/or no TCC apply. Replace the torque converter only after all hydraulic and electrical diagnoses have been made. The converter clutch material may be glazed.
7. The converter has an imbalance which cannot be corrected.
8. The converter is contaminated with engine coolant which contains antifreeze.
9. An internal failure occurs in the stator roller clutch.
10. You notice excessive end play.
11. Overheating produces heavy debris in the clutch.
12. You discover steel particles or clutch lining material in the fluid filter or on the magnet, when no internal parts in the unit are worn or damaged. This condition indicates that lining material came from the converter.

Do not replace the torque converter if you discover any of the following symptoms

1. The oil has an odor or the oil is discolored, even though metal or clutch facing particles are not present.
2. The threads in one or more of the converter bolt holds are damaged. Correct the condition with a new thread inset.
3. Transmission failure did not display evidence of damaged or worn internal parts, steel particles or clutch plate lining material in the unit and inside the fluid filter.
4. If the vehicle has been exposed to high mileage only. An exception may exist where the lining of the torque converter clutch dampener plate has seen excess wear by vehicles operated in heavy and/or constant traffic, such as taxi, delivery, or police use.

See also:
• DIAGNOSTIC SYSTEM CHECK - VEHICLE
• COMPONENT CONNECTOR END VIEWS
• STOP LAMPS MALFUNCTION