Mirror to a Face

In the attached file I have this aft at an odd angle. Is there a simple way to mirror the shaft at the end along the end face to extend the shaft? (Mirror normal to the axis of the shaft or mirror along the end face)

problem mirror.3dm.zip (83.1 KB)

Hello - set a CPlane to the end cap (CPlane >Object) then Mirror > ZAxis.
! _Cplane _Object _Pause _Mirror _Pause _ZAxis _CPlane _Undo