I have a 1993 ford explorer xlt 4.0L a4ld transmission. I just put a rebuilt tranny in in November. It has been problem free for the last 12000 miles or so. Recently it has started acting weird. If I put it in OD while sitting still it slips and barely moves forward, but if you pull it down into low gear it it locks in and rolls and shifts only If I manually work the pattern. It pulls strong no slippage in all gears. It will go into OD on the interstate but doesn't seem to want to down shift on it own when it leave the open road. I have to pull it down into 2nd gear. But then shift fine in stop and go traffic. Any suggestion are appreciated.