I had the third member rebuilt about 6 years ago. I had a 323 ring and pinion and suregrip installed. I also replaced the u joints at the same time. Ever once and a while I would notice a slight thump when I accelerated. It didn't happen all time, and I could never narrow it down. So today we are out enjoying the day, and now I'm getting a louder more noticeable thump in all three gears. Brought it home to check it out. Fluid is a little low. Doesn't smell burnt but the pinion area is extremely hot to the touch. Any ideas of what to do next. 1967 dodge coronet 500. Automatic trans. Thanks Joe