2005 Dodge Caravan Van makes loud "pop" noise whe

On a van like yours, the rear drive system requires a stiffer leverage point that both rear wheels can use to comfortably(for you)break out of it's initial inertia and get you moving, as long as it is not a deep knocking, as long as your just hearing it, that is one thing, but as you drive, it will usually only get worse. Have it lifted, have all the suspension and drive components inspected, I don't want you to get stuck and anything that may have broke puts a strain on the remaining sections of each system involved. Hope this helps you to make the proper decision. Joe It may be a broken shock, brake part, or rear drive mechanism part that failed, the rear springs should also be looked at.