Last name: Kiefer. This interesting and unusual surname is of Germanic origin, and is a metonymic occupational name for a maker or repairer of wooden vessels such as barrels, tubs, casks and vats. The derivation is from the German kief(e), kufe, itself coming from the Old High German kuofa, barrel.
Commercial Driver's License (CDL) A CDL is required to drive any of the following vehicles: Any combination of vehicles with a gross combined weight rating (GCWR) of 26,001 or more pounds, providing the gross vehicle weight rating (GVWR) of the vehicle being towed is in excess of 10,000 pounds.
CDL is required if the GVWR of the power unit is over 26,000#. (you said it was) You can license it (registered weight) for whatever you wish, as long as it covers the total gross weight of the truck and anything you have attached to it.