Clunking noise when steering wheel is moved back and forth.

What sort of noise was it? Does the noise change with the throttle or with road speed?
First check your oil levels. I'm not sure if the prowler engine shares engine oil with the gearbox or is a separate oil system. A dry gearbox can make a lot of noise AND do a lot of damage.
If the noise changes with the throttle, ( not moving and revving the engine), it could be engine issues. If the noise only happens when your moving it could be gearbox or the drive parts to the wheels.

If a brake is binding try driving in a straight line on tarmac, lightly grip the steering wheel and brake firmly. The gator will 'pull' toward the binding brake. So pulling left is a left side brake and pulling to the right is a right side brake.
Another test is to chock a wheel and safely jack up each wheel enough to clear the ground and turn each wheel by hand. A binding wheel will feel tighter or won't turn at all.

The loud rattle that you hear when the cooling system turns on and when you turn the wheels may be caused by a few different issues. Here are a few possibilities:

1. Loose or damaged components: It's possible that a component in the front of your Polaris Sportsman, such as a fan blade, is loose or damaged and is causing the noise when the cooling system turns on. Check all components in the front of the vehicle to make sure they are secure and not damaged.
2. Loose wheel or steering components: The noise may also be caused by loose wheel or steering components, such as a wheel bearing, tie rod end, or ball joint. These components can become loose over time and can cause a rattle or clunking noise when driving or turning. Check these components for wear or damage and tighten or replace them as necessary.
3. Engine or transmission issue: It's also possible that the noise is coming from the engine or transmission and is being amplified by the cooling system turning on. Have a mechanic inspect the engine and transmission to determine if there are any issues that need to be addressed.

It's important to address any unusual noises in your vehicle promptly to prevent further damage and ensure safe operation. If you are unsure of how to diagnose or repair the issue, it's best to seek the help of a qualified mechanic.

Better check the Universal Joints in all those shafts under that thing.....If one comes loose while driving it could result in expensive damage and possible injury to the rider........

Question edited for clarity.
Question moved to the correct category.

Check the universal joints on the front driveshafts.

moved you out of cars to ATV

Take directly to a professional! DO NOT ATTEMPT TO RIDE!! It will just get more expensive!!!!

Check the CV axles for play or looseness.

Look into drive system. out put shaft, U joints, tranfer case, differntrals.

The belt and pulleys are probably not the cause with the sound you are describing. To me it sounds more mechanical when you say grinding. Have you checked the rear dif?