2002 explorer here, last summer I was driving, heard a winding noise and my overdrive light kept flashing. It wouldnt shift right it was very weird. I shut the car off and turned it back on everything was fine for a while. give or take a month later I pulled up to a stop sign and went to go and at about 3000rpms I heard a very weird banging noise and didnt think anything of it nothing was different. Got to where I was going turned the car off and left about an hour later, When It would shift into second there was no gear, it would just rev until it had enough to shift and slammed into third. Had it towed in, turns out I blew straight through second gear and banged up third pretty bad. I would take it in as soon as possible just so it doesnt get any worse.