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
|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)|