First check to see if your brakes are worn. If your brakes are ok see if there's a metal dust cover behind your wheel; they can become deformed and rub against your rotor or small pebbles can get caught in them. If neither of these is the problem, lift the rear of your car ( put the rear up on jack stands and chalk the front tires so the vehicle doesn't roll ) and put the vehicle in nuetral. Rotate your rear left tire by hand and listen/feel for grinding or resistance to turning that would indicate a bad wheel bearing.
If the squeeling is coming from the tires, then the problem is most likely a misaligned front end. If the squealing is coming from the engine, then the problem would be in the power steering system.
Power Steering pump my have a leak...
Power Steering Fluid Or Power Steering Pump
Your question is vague, but since you used the words "squealing/grinding" I first start to look at the brakes. The squealing could be coming from your brake pads. Some brake pads come with a safety mechanism that alerts to when the brake pads are nearing replacement time. If you ignore that squealing then it turns to a grinding because there ain't no brake pad left. At this point, you're now looking at replacing the rotors as well as the pads. Rule of thumb is that if one side is bad then the other is just as bad or not far behind it.
The wheel bearing
The cause of the squealing sound is because you are turning the steering wheel completely to the right or left
i have a grinding noise on the front left wheel. i have taken the calipa off and i have one brake pad that is shot. could it be that or can it still be the bearing. how can i find out.
I would suspect a CV joint is bad.
Check the wheel bearings next. Since the brakes are new, the wheel bearings are probably squealing with the side pressure from turning into a roundabout.
First thought is low air pressure in the tire. Second is an alignment problem or a brake that is locking up.
Turning the steering wheel farthest left or right for a few seconds will cause a loud squealing.
Its not anything to do with the fact the vehicle is 4wd. The rear differential needs an additive added to the gear oil to keep the noise down. Go to any auto parts store and they will give you what you need. Also check the gear oil level it is probably low