Let $M$ be a smooth manifold and $p:M \to N$ a covering map. Then $N$ is a topological manifold but is it necessarily a smooth manifold? If yes, does there exist a smooth structure on $N$ making $p$ into a submersion?
If $\Gamma$ is a discrete group acting freely and properly on $M$ by diffeomorphisms then of course $M/\Gamma$ can be made smooth such that $M \to M/\Gamma$ is a submersion. My question (equivalent to it anyways) is: what if $\Gamma$ only acts on $M$ by homeomorphisms?
Constructing a counterexample may be a bit tedious. The "simplest" topological manifold that isn't a smooth manifold I am aware of doesn't have any non trivial covers ($E_8$ is simply connected).