what is a Yah sensor for 99 MB e55? on 1999 Mercedes-Benz E55 AMG

I went to a german car repair shop and they said I needed a Yah sensor ($1895.00)and new trans ($4,750.00). My car cuts out when you step on the gas and doesn't shift correctly.

Asked by for the 1999 Mercedes-Benz E55 AMG
A YAW sensor measures the rate in which the car is actually turning. When the sensor is working properly it's data input to the computer tells the vehicle how to adjust the steering and braking behavior to correct over or under steering.