30/31 SPLINE ( C6, FMX, ZF 5spd ) (9)
C6, FMX, ZF 5-speed, 4R100 AND SOME TREMEC MODELS
30/31 = SPLINE COUNT (1-dead spot = 30 SPLINE)
1.680″ BARREL DIAMETER = C6 STYLE, FMX, SOME TOPLOADER 4spd
1.886″ BARREL DIAMETER = 4R100 AND MANY TRANSFER CASES