  We find that in simulations of quasi-statically sheared frictional disks, the
shear jamming transition can be characterized by an abrupt jump in the number
of force bearing contacts between particles. This mechanical coordination
number increases discontinuously from $Z = 0$ to $Z \gtrsim d +1$ at a critical
shear value $\gamma_c$, as opposed to a smooth increase in the number of
geometric contacts. This is accompanied by a diverging timescale $\tau^*$ that
characterizes the time required by the system to attain force balance when
subjected to a perturbation. As the global shear $\gamma$ approaches the
critical value $\gamma_c$ from below, one observes the divergence of the time
taken to relax to a state where all the inter-particle contacts have uniformly
zero force. Above $\gamma_{c}$, the system settles into a state characterized
by finite forces between particles, with the timescale also increasing as
$\gamma \to \gamma_{c}^{+}$. By using two different protocols to generate force
balanced configurations, we show that this timescale divergence is a robust
feature that accompanies the shear jamming transition.
