I have a '93 Chevy Truck 1500, 5.0l, 4l60e trans. When starting out the trans. shifts fine 1st -4th gear, but absolutely no overdrive. Then a few miles down the road ,the first stop light, the trans then slams into second gear every time and only in second gear, all other gears are fine except for no overdrive. I have no lights on at all no C.E.L. no codes to pull. Any help would be greatly appreciated. Of course when the engine is shutoff for a few seconds, then start again trans will shift fine for a few stops , but no O.D. then start slamming into second again. Thanks for any ideas..