Haul truck with modular drive system

A method of retrofitting a vehicle comprising a chassis, an engine connected to the chassis, an alternator connected to the engine, a transmission connected to the engine, and a plurality of wheels connected to the chassis, the method comprising:

• removing the transmission;
• connecting a drive system to the chassis and to the alternator;
• and
• connecting a plurality of wheel motors to the plurality of wheels and to the drive system,
• wherein the drive system comprises:
• a plurality of modules,
• wherein each of the plurality of modules is directly connected to at least one other module of the plurality of modules,
• wherein each of the plurality of modules is interchangeable with another of the plurality of modules,
• wherein each of the plurality of modules includes one or more switches for controlling a mode of operation of each of the plurality of modules, and
• wherein the one or more switches of each of the plurality of modules are set to control an electrical interface between the drive system and a plurality of electrical components of the vehicle, the plurality of electrical components including at least the plurality of wheel motors.