clubman22

Hi, My 2010 2.0 TDI A4 is hitting high mileage and has a problem with the manual gearbox. I have it with my local garage to swap in a second hand gearbox from a breakers yard. The original gearbox (that is coming out) has a sensor/switch in the gearbox housing to the left had site of the gear lever. The gearbox to be swapped in does not have this. I don't have a picture unfortunately. I cannot find out what this does and if it is important. Does anybody have any ideas ?