Comfortronic is an automatic transmission with a manual shift function that is used in cars from Lancia.
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How Comfortronic works
The Comfortronic transmission is based on a conventional automatic transmission, which is equipped with a hydraulic torque converter, planetary gear sets and is equipped with an electronic control. The manual mode works on the basis of a special firmware. To activate this, the driver moves the shift lever to the appropriate position. Moving the lever to “+” or “-” engages a higher or lower gear.
Popular Comfortronic gearboxes
| Index | Manufacturer | Number of gears | Max. Torque, Nm | Max. Displacement, l | Drive type | Year of manufacture | Applicable models |
| 4HP20 | ZF | 4 | 330 | 3 ,5 | Front wheel | 1995 | Lancia Kappa; Lancia Lybra; Lancia Phedra |
| AW55-50SN | Aisin | 5 | 330 | 3.5 | Front wheel | 2000 | Lancia Thesis |
Frequent defects in Comfortronic-gearboxes
| Defects | Transmission |
| The transmission vibrates and leaks due to wear of the torque converter clutch friction plate. | ZF 4HP20 |
| The parts from the transmission pump, such as the bush, the bearings of the stator and the drive wheel fail. | ZF 4HP20 |
| The solenoid valves often fail. This is often due to contamination. | ZF 4HP20; AW55-50SN |
| The shift position sensor doesn't last long. | ZF 4HP20 |
| The bushings of the planetary gears are prone to premature failure. | AW55-50SN |