  We present a phenomenological analysis of the recent Tevatron results on the
$t \bar t$ forward-backward asymmetry and invariant-mass spectrum assuming a
new contribution from an s-channel gluon resonance with a mass in the range
from 700 to 2500 GeV. In contrast to most of the previous works, this analysis
shows that for masses below ~1 TeV resonant New Physics could accommodate the
experimental data. In general, we find that axial-like couplings are preferred
for light and top quark couplings, and that only top quark couples strongly to
New Physics. We find that composite model scenarios arise naturally from only
phenomenological analyses of the experimental results. We show that our results
are compatible with recent LHC limits in dijet and $t \bar t$ production, and
find some tension for large resonance mass ~2.5 TeV. We indicate as best
observables for discriminating a relatively light new gluon a better resolution
in CDF forward-backward asymmetry, as well as the $t \bar t$ charge asymmetry
and invariant-mass spectrum at the LHC.
