I have a reciprocating pump running 350 RPM, 2.25" stroke. Piston is double acting (ie: force in both directions). Load is ~30,000 pounds. There's a very small clearance in the coupling between piston and drive train, and this coupling goes through the same motions as the piston (it is attached to the piston). There's a ~0.003" gap between coupling and piston, so there's just a tiny bit of slapping going on. Not loud, but distinct. I'd guess the impacting loads are on the order of just a few thousand pounds. Once they come into contact, forces rise to 30,000 pounds. Contact stresses are no more than 2/3 of yield strength of the materials. Can this situation lead to non-viscious damping and potential heating of the coupling? If so, how might you calculate it?