Bump Noise in Rear.

What is your question?

My 1997 F-150 271,500 mi.ment condition, makes a bump noise in the rear when turning right or left from level pavement onto a sudden hill at 5 mile an hour. Note: This winter I'm carrying 480 lbs. of sandbags. I never heard this sound last year. What should a technition be looking for when inspecting.