What dynamic axle load transfer occurs when a tractor lifts a very heavy rear-mounted implement (e.g. heavy multi-furrow reversible plough)?

1. Load is added evenly to both axles
2. The implement acts as a lever about the rear axle, taking load off the steered front axle and making the steering ineffective
3. The front axle becomes more heavily loaded and the rear axle lighter
4. The tractor's total mass falls, because part of the implement's weight is carried by the hydraulics