I have a 97 Explorer 4x4 with a 5R55E trans. Reverse went out over 6 months ago. Backup lights come on, OD light flashes, and it acts like its in neutral. All other gears work fine except a little slipping every now and then when its cold. I dropped the pan and all was clean (no metal shavings or pieces of bands). It shows the following trouble codes: P1701 (Reverse Engagement Error), P1124 (Throttle Position Sensor out of range), P1506 (Idle Air Control Overspeed Error), and P0325 (Knock Sensor 1 Circuit Fault). I have gotten alot of different advice : neutral safety switch, shift solenoid, epc solenoid, tp sensor? I don't know what to try.