Mechanical components
The transverse automatic transmission contains three planetary trains with the accompanying brakes, clutches and freewheels. The twin shafts (a primary and secondary shaft), are located side by side. The rear (P1) and front planetary trains (P2) form the primary shaft of the transmission. P1 is a single planetary train. P2 has double planetary gear sets, an inner set consisting of the long planetary gears and an outer set consisting of the short planetary gears. The inner planetary gear, like the sun gear shaft, is common to both P1 and P2. The single planetary train P3 comprises the secondary shaft of the transmission.
The power flow from the primary to the secondary shaft passes through two intermediate gears (12, 13), and from the secondary shaft to the final drive via a driving (14) and a driven (15) final drive gear. There are a total of four brakes (B1- B4); B4 is a band brake, three clutches (C1- C3) and three freewheels (F1-F3).
A built-in oil pump (16) lubricates the moving parts of the transmission and provides the required oil pressure for the hydraulics.
Brakes and clutches are activated by shift valves in the hydraulic control system. By applying them in various combinations, four forward gears and one reverse gear can be obtained.
The torque converter has a lockup clutch. When this clutch is not engaged, some slippage occurs in the torque converter, resulting in torque ratios proportional to the slippage. When lockup is engaged, a mechanical coupling is achieved between the engine and the transmission. This eliminates slippage and results in good fuel economy. The AW 50-42 is electronically controlled, allowing lockup to be engaged in the three highest gears.