On Wed, 12 May 2010 10:00:08 -0500, "Karl Townsend"
wrote:



I'm replacing the entire PTO shaft and tightening up the clearance in the
gear box again. if everything is tight, the problem is less severe. The is
working on the symptom, not the cause.

This is a long shot, anybody know about balancing this sort of vibration or
changing the natural harmonic frequency?

Karl


What happens when you change the tension on the fan drive belts? If they are
implicated at all, that'll change the resonant frequency. It's a bit far to
drive over to Blighty so we can instrument it up and workout where the
resonance is :-(

Mark Rand (Did similar work on power station foundations once)
ETFM