Catalyzes the epimerization of the C3' and C5'positions of dTDP-6-deoxy-D-xylo-4-hexulose, forming dTDP-6-deoxy-L-lyxo-4-hexulose. Involved in the biosynthesis of the dTDP-L-rhamnose which is a component of the critical linker, D-N-acetylglucosamine-L-rhamnose disaccharide, which connects the galactan region of arabinogalactan to peptidoglycan via a phosphodiester linkage. dTDP-4-dehydro-6-deoxy-alpha-D-glucose = dTDP-4-dehydro-beta-L-rhamnose Carbohydrate biosynthesis; dTDP-L-rhamnose biosynthesis. Homodimer. Was identified as a high-confidence drug target. Belongs to the dTDP-4-dehydrorhamnose 3,5-epimerase family.