[davepl]

My problem was different in that it showed up at low speeds, but it turned out to be the splined section of the slip joint was worn. Or at least that's the last thing we did before the problem went away. So the whole driveline seems pretty sensitive and that slip joint in particular. I can't explain the harmonics or magic that made it shake, but it shook back until we fixed that. I still don't understand it though.