01 Forester makes buzzing noise when accelerating pitch gets higher stepping on gas and gets lower when coasting to lower speed seems to go along with change in rpms new LF axle inaudible at 65mph?

You should check if the clutch is still OK. When it gets worn out, the engine 'races' to high revs ( with high pitch) when you accelerate. When driving without much load on the engine, that is, for example, coasting on the straight and a higher speed, the engine will sound fine but try to accelerate harder and the 'revving up' will show up again.