Last week the 4wd sensor was replaced as the service light has been going off & on for awhile. Also, I speedometer cluster was replaced as the speedometer worked sporadically. Exactly one week later my transmission stoppped shifting properly and now is not driveable, however, I had no previous problems. Also, their was not tranmission leakage and the fluid was clean. Car dealership said the previous week's repairs are not related. Any ideas? Is there a sensor involved?