  We present fully self-consistent calculations of the thermodynamic properties
of three-dimensional clean SNS Josephson junctions, where S is an s-wave
short-coherence-length superconductor and N is a clean normal metal. The
junction is modeled on an infinite cubic lattice such that the transverse width
of the S is the same as that of the N, and its thickness is tuned from the
short to long limit. Both the reduced order parameter near the SN boundary and
the short coherence length depress the critical Josephson current $I_c$, even
in short junctions. This is contrasted with recent measurements on SNS
junctions finding much smaller $I_cR_N$ products than expected from the
standard (non-self consistent and quasiclassical) predictions. We also find
unusual current-phase relations, a ``phase anti-dipole'' spatial distribution
of the self-consistently determined contribution to the macroscopic phase, and
an ``unexpected'' minigap in the local density of states within the N region.
