A steering shaft can go bad due to normal wear and tear although most steering shafts last the life of the vehicle.
The signs of a failing steering shaft include.
A vibration that increases with speed.
A shudder or vibration upon acceleration.
A humming or growling sound while driving.
A clunking sound while accelerating.
Wandering of the vehicle from side to side when driving.
A shimming in your steering wheel, especially when driving at high speeds.
And a knocking noise when you hit bumps.
A steering shaft is very important to a vehicle and your safety and other peoples safety.
The steering shaft helps to steer the vehicle and keep the vehicle in control.
Your steering shaft connects your steering wheel to the steering gear which allows you to turn the wheels of the vehicle.
Your steering shaft also allows you to adjust the height of your steering wheel, which can also help create a safe and ergonomic seating position.
If your steering shaft goes out you can and will lose control of the vehicle and at high speeds that can lead to serious injury to death.