  In order to extract transport quantities from energy-momentum-tensor (EMT)
correlators in Lattice QCD there is a strong need for a non-perturbative
renormalization of these operators. This is due to the fact that the lattice
regularization explicitly breaks translational invariance, invalidating the
non-renormalization-theorem. Here we present a non-perturbative calculation of
the renormalization constant of the off-diagonal components of the EMT in SU(3)
pure gauge theory using lattices with shifted boundary conditions. This allows
us to induce a non-zero momentum in the system controlled by the shift
parameter and to determine the normalization of the momentum density operator.
