Jack up one front wheel and try to move the wheel holding it at 6 and 12 o clock and at 3 and 9 o clock. If there’s play at 3 and 9, take a look at your tie rod ends, if there is play in them or if the bushings are torn. If they look ok and have grease fittings I’d grease them up. If there is play at 6 and 12 I would look at your upper and lower control bushings to the frame and the ball joints themselves. If it moves no matter where you grip it, it could be the bearing .You can use a pry bar on these parts to get an idea how much play they have while driving and if it’s worth replacing them. but this issue could be other things like a rear wheel bearing going bad, swAy bar To frame bracket bushings being worn out, maybe a problem with the cv axle or an issue with the tires.
ive had 5 explorers, three of them 3rd generation. Tie rods inner and outer are easy to replace, use a pipe wrench for the inner. Upper control arm is easy to replace, use a Pittman arm puller to separate the ball joint from the knuckle, takes a bit to finagle the control in and out of the engine bay through the wheel well, there are a couple flimsy plastic parts on the driver side be careful not to break them. If it’s the bearing just replace the hub assembly much cheaper and easier than having a mechanic replace the bearing.
