I have numerous hitches in my truck for different trailers and installation heights. The annoyance is the amount of rattle/noise that comes from them not fitting anywhere close to tight inside the receiver. Going over bumps drives me crazy, so I found a simple solution for addressing the problem. Foil tape! The same stuff that you use to seal duct work and available at any home improvement store.
The problem with most of my hitches can be solved with just a few wraps of tape both in front of and behind the pin hole. If there is more space than just a few wraps of the thin foil, simple cut a thin strip of sheet metal and incorporate it under the tape. Some trial and error in adding or removing layers of wrap will yield a tight fit and rattle-free installation. Eventually the tape gets pounded flat and needs to be reapplied, but it will last for a lot longer than one would think. If you need to reapply as time goes by, it's only pennies to re-do it.
Here's a picture of one of the hitches that has tape from 5 years ago still on it.
