A Bad Transmission make the vehicle totally unreliable. Because transmission failures are expensive to fix, and no one wants to deal with a bad transmission. Automatic Transmissions can fail due to many reasons, including harsh shifting habits and manufacturer defects. Its not just every CVT (continuously variable transmissions) are bad. Consumer Reports data show that some models carry a significantly greater failure rate than other models. If you are on the market for a used-car, avoid these 10 vehicles.