[A bones]

Not understanding. If you mean all the time while moving, I'd say check each wheel ( 4 ) for out of true. If you mean at certain speeds, then it is possible it's a balance issue.

It is also possible that you need parts, or adjustments. Begin with the front spindle bearings. Then check tie rod end king pins etc.

The triple gears may be worn, however if this occurs while moving I'd be suspicious of the frond end assembly.

More description of the symptom would help in figuring this out. Good Luck