check Power Steering fluid and pumps, rattle could be anything from exhaust fittings to in the dashboard, so would need to take to a garage.
sounds like a bad power steering pump
You'll be driving in the dirt/grass.
You probably have torque wrap from driving in 4WD on dry pavement. Get off the pavement and try disengaging.
it could be your tires on the pavement.
Steering fluid leak.
A car's steering wheel will vibrate when driving if the car's alignment needs to be adjusted.
If the steering wheel is loose while driving the steering rack may be going bad. A bad steering rack leads to a lot of play on the actual wheel.
Your tires are bad or you need an alignment. Get your tires checked, they may need to be replaced or rotated, and you can check your alignment by letting go of the steering wheel while driving, if it drifts left or right significantly, you need an alignment.
The only dangers that might arise from driving a vehicle with a failing power steering pump is burning up/breaking the belt that is driving the pump IF and ONLY IF the pump seizes up. The other problem you might have is the increased effort to steer the car. As long as the increased effort while driving is not a problem you can at least drive it to a service station to get it repaired.
Apply the brakes immediately and swing the back onto the pavement quickly
A steering wheel that is padded with leather for comforment when driving
are you driving on a smooth road ? some of the 4 x4 will shudder on even pavement. Remember 4 x4 driving assumes your on rough or uneven surfaces. But just to be safe have it checked at a transmission service center.It is slightly possible a driveshaft joint has dried out causing this but is is rare.