My 2000 CRV automatic will not shift into the overdrive gear, and my mileage is suffering accordingly. The overdrive switch on the column shifter is working, so I know the O/D is activated, but it will not shift up to the highest gear. My mechanic put a transmission fluid "treatment" in, which helped a little bit, but now that temps are lower (and the car sat for a while, about a month) it will not shift again. Any help would be appreciated in keeping the old girl on the road!