I have a 1999 2.8iTD Ducato Autotrail motorhome. The problem I have is that the speedo occasionally decides it won't bother indicating what speed I am doing. This happens about once in every 10 or so journeys, but the odometer still keeps registering the mileage. I've read on some other posts about problems with a gearbox sensor, but does this older van have a sensor fitted? Can anyone help please?