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