gcliburn

A friend of mine has a 99 cab chassis 4wd. he just changed the rear end and it needs a set of axles. Does anybody know where to look to determine what length they are, I know they are shorter in a cab chassis, and wondered if a 3/4 and cab chassis had the same length axle and a dually pickup had a longer one. Sorry if this is in the wrong place, but I am 200 miles from the truck and trying to help him. Thanks