X52725500008 is a correct like for like supersession to original 5242500401 of the steel version flexplated flywheel assemblies – the only difference between them is the actual steel flexplate center sections has changed part numbers from 5141806 to ...
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 ...
Please see below and attached details for Geislinger isolated Flywheel installation tensions. Please also ensure following - - if replacing steel flexplate ensure alternator suits and has clearance for this coupling version. - if replacing steel ...