  We discuss if the Tevatron ttbar asymmetry can be explained by T-channel
exchange of a W' gauge boson coupling to down and top quarks. In a
spontaneously broken gauge theory, such a W' is necessarily accompanied by a Z'
at a similar mass scale. Null results from Tevatron searches for dijet and
dilepton resonances imply large mass splitting between the $W'$ and $Z'$. We
argue that such splitting can only be accomplished if the gauge symmetry is
broken by a scalar in a large dimension representation of the gauge group, for
which no perturbative description exists.
