Front End Noise - Wheel bearing?

[95beater]

I've looked through the other posts and I have a problem that doesn't quite fit.

I've got a 2003 Expy 4x4 with the 2H/AWD/4HI/4Lo tansfer case. It has 161,000 miles. Recently at highway speed (70mph) the left front wheel starting making an almost constant high pitched/metal to metal squeal. I was in AWD. I pulled off the road it made the noise at roughly the same pitch to 10 mph. The neither wheel was hot to touch. I got back on the road and it didn't do it for again for 45 minutes. The noise doesn't change if I hit the brakes or shift into AWD, 4HI, or 2H. There was a very slight change in pitch if a changed lanes. It would get better and worse for the rest of the trip and would usually get bit louder above 70.

I just got home and jacked up the front. Neither wheel has any back and forth motion if I grab and put force on the wheel from top to bottom and there is no noticable noise if I spin the wheel. The only noise from spinning the wheels is the gears in the auto hubs/CVs engaging for the first inch or two or spin (this sound seems normal). It appears as if the hubs are engaged in 2H with the engine running (is that the way its supposed to be?)

Anyway!? Is this the front unit bearing or something else? I have $600 worth of bearings in the trunk and I wanted a second opinion before I started the work.

 

[95beater]

Well....I took off left (noisy) and right (not noisy) wheel bearing units and found that both of them had bearing "dead spots" i.e. spots where you could feel the internal bearings were going bad when you spun it in your hand.

When off the truck (not attached to the knuckle/cv shaft) try spinning the hub slowly in your hand, if going bad (or just bad) the bearing feels smooth for most of the rotation but at some point its not very smooth. I may be wrong here, but this had been my experience in the past when I had an Explorer that I drove forever and into the ground and replaced the front wheel bearings, twice.

For the Expediation I replaced both hubs last night and so far it sounds great. However, I'm not 100% convinced that this was the problem. I wouldn't be surprised if I found out later I had a U-Joint going bad, a CV joint on death's door, or the left side bearing in the axle tube singing the blues (the right tube bearing was replaced last year along with the seal due to a leak. Worst job to do at home, ever)

Futhermore, I found that the vaccum hubs have gone bad and are stuck in "defualt" mode, which is engaged so that the front wheels are always engaged even if its in "2HI". Really its the right side that is in the worst shape since the toothed engagement ring wont freely move in to disengage the hub.

I kinda don't care since I always run it in 4AWD since I live in rainy/snowy northern Illinois. I believe the replacement vaccum hub part (ford calls it the "actuator?) is about $100 per side and then there is a vaccum swich that sits on the fire wall for another 30 bucks. I'm guessing this is also bad too since it won't disengage the right ring, which does move freely.

With that said, I'm thinking about replacing these parts for about $230 plus tax to save an MPG in 2HI if I get bored. If anywone cares, I'll post this information when I get around to it.

 

[95beater]

If you have a Haynes Manual for a 2003-ish Expy, the torque spec for the end of the CV shaft/hub nut they list is wrong. Its actually 20 ft-lbs...not several million (or what ever they wrote, 140-220?). If you are confused, the 20 ft-lbs spec is for a smallish 13mm nut.

 

[95beater]

Just in case someone finds this someday and wonders "was this resolved"....

I've put over 1000 miles on it in 3 weeks and the noises are gone. It was the wheelbearing.

While I had it apart I also found that both of the front vacuum hubs are bad so I am driving around in "2H" the front axle is locked. In AWD it kicks in the transfer case and I have AWD. The right one was the worst, the ring will not retract with finger pressure.

 

[colemanwhite123]

My problem now is when I turn the wheel bearing, at any speed, to the left I get some impressive vibration in the steering wheel.