Speed sensors CVT

Some Audi owners experience drivability problems after a valve body is replaced on their CVT transmission. After a closer look at this situation, many times we found out that the failure comes from improper handling and wrong disassembling or reassembling of their transmission.
When the valve body is removed from the back of the transmission, you see two big rubber seals, they look like regular clad seals, but they are very important Rpm sensors. These sensors get bent or damaged very easily. But the two big rubbers looking seals are two hall sensors magnet wheels. With the info from the hall sensor the control unit is recording the

hallsensor

input speed and the output speed and also the Rpm direction. This setup gives the integrated control unit the possibility to control the reverse speed, or it detects if the car goes reverse or forward. If the sensors are damaged, the car has all kind of drivability problems.