a steering assist valve configured to selectively operate at least one said turn assist cylinder and thereby bias said corresponding caster wheel assembly during an operator commanded turn, said {HEAD ~ steering assist valve} including {TAIL ~ an input gear}; and 
including
a steering assist valve configured to selectively operate at least one said turn assist cylinder and thereby bias said corresponding caster wheel assembly during an operator commanded turn , said { HEAD ~ steering assist valve } including { TAIL ~ an input gear } ; and
OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH OTH HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH