  We study the twisted Ruelle zeta function $\zeta_X(s)$ for smooth Anosov
vector fields $X$ acting on flat vector bundles over smooth compact manifolds.
In dimension $3$, we prove Fried conjecture, relating Reidemeister torsion and
$\zeta_X(0)$. In higher dimensions, we show more generally that $\zeta_X(0)$ is
locally constant with respect to the vector field $X$ under a spectral
condition. As a consequence, we also show Fried conjecture for Anosov flows
near the geodesic flow on the unit tangent bundle of hyperbolic $3$-manifolds.
This gives the first examples of non-analytic Anosov flows and geodesic flows
in variable negative curvature where Fried conjecture holds true.
