Using the stochastic Langevin model coupled with a statistical decay model, we study nuclear dissipation properties at large deformations with excitation energy at scission (E*sc) measured in experiments. It is found that the postsaddle dissipation strength required to fit E*sc data is 12 ×1021 s-1 for 254;256Fm and 6 ×1021 s-1 for 189Au, which has a smaller postsaddle deformation than the former heavy nucleus, showing a rise of nuclear dissipation strength with increasing deformation.