X52725500009 - Geislinger isolated flexplate coupling
X52725500009 is the newer version Geislinger isolated flexplate / coupling design that Hitachi have in place of the typical steel version of X52725500008 or 5242500401 as new truck supply.
Note if an existing unit is updating / installing this later isolated flexplate must ensure alternator is suited and that crankshaft endfloat is not hindered and must verify on installation.