A planetary gear reduction system 5, wherein said casing includes a first member and a second member abutting {HEAD ~ opposing ones} of {TAIL ~ said axial ends} of said internal gear 
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A planetary gear reduction system 5 , wherein said casing includes a first member and a second member abutting { HEAD ~ opposing ones } of { TAIL ~ said axial ends } of said internal gear
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 REL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH