If the shaking happens at a certain speed, like if as soon as you hit a certain mph it starts to shake then it is quite possibly an alignment issue or wheels out of balance.
If it has a whirring sound associated with it then in my experience it it usually something out of balance which could mean something is not bolted snugly, I had that happen when a lug nut was loose also when the half shaft bolts werent torqued correctly.
I'm no expert by any means but that should at least give you a start.