Probably involved in the biosynthesis of the acarviose moiety of the alpha-glucosidase inhibitor acarbose (PubMed:10196166). Catalyzes the dehydration of dTDP-D-glucose to form dTDP-6-deoxy-D-xylo-4-hexulose via a three-step process involving oxidation, dehydration and reduction (By similarity). dTDP-alpha-D-glucose = dTDP-4-dehydro-6-deoxy-alpha-D-glucose + H2O Binds 1 NAD(+) per subunit. Homodimer. Belongs to the NAD(P)-dependent epimerase/dehydratase family. dTDP-glucose dehydratase subfamily.