A hydraulic motor is coupled to {HEAD ~ a front pair} of wheels rotatably mounted to {TAIL ~ the front frame section} 
A hydraulic motor is coupled to { HEAD ~ a front pair } of wheels rotatably mounted to { TAIL ~ the front frame section }
OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL