A vehicle drivetrain can include various structures, such as a multi-ratio transmission, a two-speed final drive assembly connected in series with the multi-ratio transmission and including a low speed final drive ratio and a high speed final drive ratio, a pair of front driveshafts driven by the two-speed final drive assembly, a pair of rear driveshafts, a rear differential assembly connected to the two-speed final drive assembly, and a control assembly including. The control assembly can include a controller in electrical communication with portions of the rear differential assembly, such as a variable displacement pump and purge valve. An input array can be in electrical communication with the controller and can include a plurality of sensors, and at least one switch accessible to an operator of the vehicle. Various related methods can also be executed for control and operation of such a drivetrain. The methods can incorporate a number of variables in order to control the drivetrain, and the variables can include but are not limited to road grade, vehicle acceleration, vehicle speed, presence of towing apparatus, road surface conditions, switch condition(s), etc.