'05 CRD, 2.8 Diesel - at about 65 mph my transmission downshifts out of overdrive. It does not shift into 1st gear when I come to a stop and requires me to reach 3000 rpm to shift into the next gear (2nd, 3rd, 4th etc). When I shut off the motor and let the computer reboot, it all goes back to normal until the next time, which could be a day or a week or a month. Anyone familiar with this problem?