Way back when, some car company had a vehicle called a ForeRunner, and not to be outdone, some other one had a PreRunner.
Well, I named my beat up old pickup truck "DumpRunner".
Somehow, the name has stuck, and as one truck gets retired, or more likely, dies in harness, its replacement inherits the name. The current Dumprunner is a 2000 F-150. Not really old enough yet, but a few more seasons of driving through the brush at deer camp will put the right patina of scratches on the paint...