Shear viscosity of pure Yang-Mills theory at strong coupling

We calculate the shear viscosity to entropy density ratio in pure SU(N) Yang-Mills theory below the critical temperature using the strong coupling expansion. The result for the eta/s ratio for temperatures around the phase transition is 0.22 for N = 2 and 0.028N^2 for N > 2. The results are consistent with the conjectured 1/4pi lower bound inspired by the AdS/CFT correspondence.