I have a 1999 C230 Kompressor and have ordered a used wiper transmission to replace my failed one. Any secrets to replacing it? I've removed the air vent plastic parts and see three nuts. I'm just not sure about taking the arm off and replacing it. I found the directions on replacing the motor, and, if it helps, they referenced the following for removing the assembly - AR82.30-P-6400E, and for setting the wiper arm - AR82.30-P-6800-02E. Thanks!!