About a couple of months ago my MDS started to make the ratcheting noise, could get rid of it by putting the gear select to 8+... seemed easy enough but to it seemed like something had "broken" and I felt that I should get if fixed before I shut it off. Recently I did not select the gear button and have been driving with MDS on to see if there still there, and wouldn't you know it the sound is gone!.. tried all the ways, coasting down from around 45mph, making sure window it open and driving by buildings to hear it... nothing! So my question is, what happened to make the noise and how did it fix itself? I don't know enough about the MDS functionality other than it is shutting down cylinders. Now that it seems that it is working properly I think I want to shut it off... anyone using the Diablo piggy back tuner? Thanks