noises

I have a 99 Tahoe, its on the way to being mechanically finished, Ive noticed a noise kind of a clicking or grinding sound that comes from underneath , cant tell for sure but sounds like its under the front or middle. Ive changed the U joints and fixed that issue, it went away somewhat after...

Hello!! Bought a 2014 Tahoe LS 4WD and runs perfectly fine just what are those clunking sounds underneath at rear sounds like (marble hitting aluminum can, etc.) 10sec intervals right after I shut off the engine? Could it be metal cooling down or is this normal?