Q: I have a problem with my C240 - the gear won't shift from one

Since your question is not very specific, I will address a couple of situations. If by "my gear won’t shift from one to others" you mean the shifter will not move between park, reverse, and drive, that can be caused by a couple of different things. If the brake light switch is bad, it can prevent the shift interlock from releasing, keeping the shifter from moving. Also, the shifter mechanism itself can have an electrical or mechanical fault which prevents the shifter from moving.

If you mean that once in Drive, the transmission will not shift up through the forward gears, then other issues can cause this. Low transmission fluid levels can prevent the transmission from shifting. The transmission works using hydraulic pressure to shift gears. low fluid or poof fluid condition can prevent shifting. The transmission control module - the electronic brains of the transmission - may also be at fault.

In either case, a certified technician can diagnose the exact cause for you.