Had a used tranny put in August last year. A few weeks ago when I let off gas pedal to make a turn or going down a hill it acts like it goes into neutral. I rev motor and it jumps back in gear. Cut overdrive off and it won't do it. Then it got to where I had to rev motor at start up or anytime I stopped and keep overdrive cut off for it to go in and stay in gear. Reverse works fine. Once in gear it never slipped or hesitated. I checked fluid level and it was above full. Got it down to normal level, no help. All of a sudden now all I have is reverse. No forward gears whatsoever. I dropped pan. Factory dipstick tube plug was still in it but also this little round metal thing that's broken off from somewhere. 1/4 in. high. About size of dime in diameter. It looks as if it had a lip extending out from one end. Half of lip is still there. It's not the magnet. Magnet is still in place. Found no metal shavings but don't know where the rest of the broken piece is either. I have a picture of it on my email but don't know how to load it on here. Any help is appreciated. Not a mechanic at all. Thanks