2000 Ford Explorer noise in the front wheel

First look at how you tightened the axle nuts. A lot of people put the wheels on, then set them on the ground to hold the axles from spinning. Doing that will instantly make the new bearings noisy. They must never have any weight on them unless the axle nut is torqued to specs with a click-type torque wrench. The second common mistake is some people just make those nuts tight but not with a torque wrench. The torque values are fairly critical. Most bearings call for around 180 foot pounds but some go as high as 240 foot pounds.

There is a tool you might be able to borrow or rent from an auto parts store that borrows them called the "Chassis Ear". It is a set of six microphones, a switch box, and headphones. You clip the microphones to suspect points, then drive around while listening with the headphones. You can move the microphones around to zero in on the source of the noise. Be aware that many mechanics have never seen or even heard of this tool. Suspension and alignment mechanics use it to find rattles, squeaks, and other noises.

I actually did have something like you described once but I don't think it applies to your vehicle. The noise only occurred after about five minutes on a test drive, and it couldn't be duplicated in the shop. It had to be in cold weather too. It finally dawned on me that the noise only occurred above 45 mph going out of town, but at lower speeds coming back when the wind was blowing toward me. It ended up being bad bearings in the electric AC condenser fan motor. It would spin in the wind and howl, and once it started, the noise wouldn't stop until about 10 mph.

Think about that Chassis Ear. The guys on the tool trucks sell them for $200.00 but I've seen them on Amazon for less than half of that. There's a wireless version too where four of the microphones are wireless and two still have wires like on the original version.