Scharlemann gave an example of a 4-manifold admitting a fake homotopy structure on S3 X S1#S2 X S2, which is homeomorphic to S3 X S1#S2 X S2 by a theorem of Freedman. We address the problem whether a Scharlemann's manifold is diffeomorphic to S3 X S1#S2 X S2 in terms of 2-knots in S2 X S2.