1. Gross Vehicle Weight Rating (GVWR): Check the GVWR of the 03 F-550 Diesel and the Case 580 Backhoe. If the combined GVWR of the tow vehicle and the towed equipment exceeds 26,001 pounds, a Class A or B CDL may be required.
2. Air Brakes: If the trailer (Case 580 Backhoe) has air brakes, a CDL with an Air Brakes endorsement is required to operate the combination.
3. Commercial Purpose: If you are using the vehicle combination for commercial purposes, such as transporting the backhoe for hire or business, you may need a CDL.
It's always advisable to refer to the latest regulations and consult with the New Hampshire Department of Motor Vehicles (DMV) or a qualified legal professional to confirm the specific requirements and exceptions for your situation.