Greetings!
I have a few questions in order to help with your situation.
1) Does the problem occur when you are sitting still or when you are moving? Or both?
2) Does it occur in all gear ranges, (High, Medium, Low)?
3) Is there any particular speed it intensifies at? (Turtle - Rabbit)
Thank you for being a valuable TYM customer, I'd be glad to assist in anyway possible!