Thanks for all the replies. Sorry for my slow response. Per the transmission supplier, the gear mesh is 1000 Hz (frame's natural frequency) only when it is in fifth gear and the engine is spinning at 1500 rpm engine. The vibration requires high throttle, but went away when transmission was put...
I got an old bus frame that gets excited by the powerpack and creates an unacceptable ringing noise when it is in 5th gear and at 1500 rpm engine speed. I am looking at changing the axle ratio to reduce the eng speed at cruising speeds. But I was wondering if filling 2" X 3" frame members with...
