Are you sure the alarm is discharging the car? This model of C class has a very common issue with amperage draw of the battery by the seat control modules. Both of your front seats have control modules underneath the seat cushions. When these modules fail they stay on all the time causing a slow amperage draw of the battery when the vehicle is off. So when you try to start the car first thing in the morning your battery is dead because the modules were on all night. You can disconnect these modules from the front of the seats. They are located directly under the seat cushion ( module is a small 4"x6" black box) and will have a connector you can disconnect. Only trade off is with these unplugged you will have no seat functions.
As for the shifting problem, you may have a failed shift gate solenoid. This solenoid allows you to shift into gears. You can usually jolt the solenoid loose by hitting the top of the gear selector in a hard, straight down motion with a heavy object like a book. When you do this make sure you are pulling firmly on the gear selector at the same time. This problem will eventually lock you out completely. The fix will require replacememnt of the shift gate module.
Tuesday, January 6th, 2009 AT 4:34 PM