You will get a lot of answers here but the 2 times I had chucking the 5th wasn't level. Once I leveled it out most of the chucking stopped. When I brought home my current 5th the chucking was so bad I thought the 5th was coming off. After adjusting the hitch height so the 5th was level it stopped. That is the first and cheapest place to start.
Bill & Linda. If it doesn't move and should, WD-40 it. If it moves and shouldn't, duct tape it. F-350 dually, 40' Sunnybrook Titan toy hauler and custom Harley