Front differential bearing

These video might ive you some idea:


How to Replace Front Wheel Bearing


Replace Front Wheel Bearing Hub Ford Taurus Mercury Sable


How To Install Replace Front Wheel Hub Bearing Taurus Sable 96 06 Part 1...


How To Install Front Wheel Bearing Hub Assembly 2002 05 Ford Explorer...

What you want to do is engage the system and then kill the engine. This will work with electric hubs if you leave the keyswitch on.

With the front tires off the ground, a locked hub should turn the c-v joint and try to turn the front differential. If the transfer case is locked in 4x4 then the front driveshaft should be locked too. The differential is caught in the middle. It may have spider gears which can break, but if the c-v joint turns something is not connecting inside the front differential.

If the front hubs are Vacuum activated, you should be able to apply Vacuum and do the same test.

does it get louder above 45-60mph? and much quieter at low speeds. It could be wheel bearings, a rear differential or front differential. If its a grinding humming noise its wheel bearings, listenin to see if theyre coming from the front or rear, left or right, or both when your driving to know what wheel bearing are bad. If its a whinning noise, its probably a differential. check and listen to hear if its coming from the front or rear. Also, check for loose plastic around the wheels. Lastly check your tires for uneven or choppy wear. move your hands front to back on the top of the tire. does it feel really choppy and rough, maybe you just need new tires

I would dismantle the axle, fit new thrust bearings and anything else that is worn/damaged and reassemble/adjust clearance gaps to it, according to the service manual.

has anyone checked the front drive shaft u joints, play in the differentials? differentials would come and go as you accelerated and let off.

That will be a Huge job. The whole front diff must come out of the car and the case will need to be taken apart to even gain acess to the carrier side bearings.
The hub bearing is where the wheel bolts up is that maybe what you are talking about?
Also the axle seal isn't that bad to do you need to remove the cv shaft then it's just a simple remove the seal and install the new one.
But all of these jobs will be big ones.

Worn side bearings is where the noise is coming from and might as well do both sides, I used replace them in about 2-4 hours, depending on where Murphy happened to be. Disconnect both side inner CV joint, front prop shaft and the 4X4 actuator line. If you want to drop the front pumpken. Not sure if you have enough room if you want to change the bearing without removing the pumpken from the frame. You should see when you disconnect the CV shaft.

The front diffs are toys compared to the rear, if you use auto4wd too much there are bearings in your tranfer case that are similar to the side bearings in the front diff. In both appearance and durability and soon you'll replace those too.

Good luck and keep me posted.

bad hub bearing

You can't just replace the bearings. You've got to replace the entire wheel hub (thank you genius engineers at Chevy). My driver side front wheel was rubbing the frame and the hub cost around $350 plus $150 labor.

Sounds like the front axle electric actuator is bad. these are mounted on the front differential housing. they are known to go bad.