Sentronic is a marketing name of several automatic transmissions with a function of manual gears shifting installed on Saab cars. They debuted in the early 2000s when the second generation of Saab 9-3 and Saab 9-5 models entered the market.
Operating principle of Sentronic
The main components of this transmission were planetary gears and a torque converter with a lockup function in certain modes. In manual mode a driver could use engine torque with maximum efficiency, which had a positive impact on vehicle dynamics, increasing its performance on slippery surfaces, rough roads, and when driving downhill. To switch to the manual mode, a driver should move the gear lever into the “M” position. Pushing the lever to “+” or “-” was used for up- and downshifting respectively. The paddle shifters were offered as well.
Popular Sentronic transmissions
Gearbox code | Manufacturer | Number of gears | Max engine capacity, L | Max engine torque, N–m | Car layout | Production start | Model applications |
FA57 (AF33, AW55-50SN) | Aisin | 5 | 3.5 | 330 | FWD | 2000 | Saab 9-3; Saab 9-5 |
AF40-6 (AWTF-80SC) | Aisin | 6 | 2.5 | 450 | FWD, AWD | 2001 | Saab 9-5; Saab 9-3 |
Common malfunctions of Sentronic transmissions
Malfunctions | Transmissions |
The solenoids get clogged with wear products of the friction linings in clutch packs. | FA57 (AF33, AW55-50SN) |
Oil starvation leads to wear of the mechanical transmission elements. | FA57 (AF33, AW55-50SN) |
The valve body and planetary gear bushing fail. | FA57 (AF33, AW55-50SN) |
There are jerks after a certain mileage. They indicate the malfunction of the valve body. | AF40-6 (AWTF-80SC) |
The brake band wears out. | AF40-6 (AWTF-80SC) |
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