  We use gauge/gravity duality to study the dynamics of strongly coupled gauge
theories undergoing boost invariant expansion in an arbitrary number of
space-time dimensions (D). By keeping the scale of the late-time energy density
fixed, we explore the infinite-D limit and study the first few corrections to
this expansion. In agreement with other studies, we find that the large-D
dynamics are controlled by hydrodynamics and we use our computation to
constrain the leading large-D dependence of a certain combination of transport
coefficients up to 6-th order in gradients. Going beyond late time physics, we
discuss how non-hydrodynamic modes appear in the large-D expansion in the form
of a trans-series in D, identical to the non-perturbative contributions to the
gradient expansion. We discuss the consequence of this trans-series in the
non-convergence of the large-D expansion.
