Various vehicle systems capable of different operation modes are disclosed. According to one example, the system can include at least one input shaft, at least one output shaft, a plurality of hydraulic devices, and one or more accessories. The plurality of hydraulic devices can be configured to be operable as vane pumps in a retracted vane mode of operation and can be configured to be operable as a hydraulic couplings to couple the at least one input shaft with the at least one output shaft in a vane extended mode of operation. The plurality of hydraulic devices can be simultaneously operable as the hydraulic couplings and the vane pumps. The one or more accessories can be in fluid communication with the plurality of hydraulic devices and can be configured to receive a hydraulic fluid pumped from one or more the plurality of hydraulic devices when operating as the vane pumps.