Just ordered and recieved a "rebuilt" compressor for my 300E, 1990. Calls for a 10PA17C. As I look at it I notice that there is not a "speed sensor" on the rear of the compressor as there is on the original. I have not started the replacement yet. Question is this: Is the speed sensor required? can it be taken off the old compressor and installed on the rebuilt one. I would hate to start the job and have to stop if this unit is not compatable.