92 Ford Explorer with A4LD automatic. Transmission will not disengage from drive. Drives and shifts smoothly when in drive position. When shifted to neutral, responds as though still in drive. When in reverse, it is though I put the parking brake on while still in drive. Park seems to be the same way as reverse. Note my description of Park and reverse. Reverse feels like it is in both reverse and drive at the same time and the engine canot be revved because of the strain against the transmission. Park seems to engage the parking paul, but does not release the drive and therefore I cannot rev the engine. There is back pressure against the engine. Any suggestions. High mileage (>140,000 miles). Willing to do some exploration for a simple fix, but if faced with a rebuild I will either swap it out myself or find someone who will swap it out with my choice of transmission rebuild brand (depends on the warranty conditions).