Hello good people,
So recently driving my f150 that has 27,000 miles on it, down the road. Driving through the city, I hear a clunk in the rear end. I tried to figure out where the sound was coming from and when it did it. My conclusion came when I was at a high rev and let go the throttle and on its downshift it did it. It was happening from 3 rd gear to 2nd gear. It gets better. A few days later driving down a road a approximate 30-40 mph it started to slip. I turned the over drive off and the issues gone. The clunk sounded like a rear end issue now this. I've read all the treads on tranny issues but I don't think they are related to my issue. If Anybody can help. I would appreciate it.

Thank you,
Sako