What is Comfortronic? Features & technical parametres of the gear box

What is Comfortronic? Features & technical parametres of the gear box

Comfortronic is an automatic transmission with a manual gear shifting function, installed on Lancia cars.

Comfortronic operating principle

The Comfortronic transmission is based on a classic automatic gearbox with a hydraulic torque converter, planetary gear sets, and electronic control. The manual mode uses specialised firmware. In order to activate it, the driver moves the gear lever into the corresponding position. Moving the lever towards “+” or “-” shifts gears up or down.

Popular Comfortronic transmissions

Gearbox codeManufacturerNumber of gearsMax torque, N·mMax engine capacity, LCar layoutProduction startModel applications
4HP20ZF43303.5FWD1995Lancia Kappa; Lancia Lybra; Lancia Phedra
AW55-50SNAisin53303.5FWD2000Lancia Thesis

Common malfunctions of Comfortronic transmissions

The transmission starts vibrating and leaking due to the torque converter friction plate wearing out.ZF 4HP20
The transmission pump parts such as the bush, the bearings of the stator and of the drive gear break down.ZF 4HP20
The solenoids break down often. Their breakage is usually caused by soiling.ZF 4HP20; AW55-50SN
The gear position sensor has a short lifespan.ZF 4HP20
The bushes of the planetary gear sets are prone to premature breaking.AW55-50SN


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