Hi,

I have an 03 Exp 4x4 Limited with 4.6L V8 with 167K on the clock. I'm getting a kind of humming rotating sound out of the front end when moving. The frequency definitely goes with the wheel rotation speed and the noise is the same with the trans engaged and when coasting in neutral. The noise is present at all speeds but becomes more of a humming sound as the speed increases at highway speed.

I've had both front wheel bearing hubs replaced (they were completely shot), brake pads and rotors replaced, and just had new tires. The rotating sound is still there though. What else is there that could be the cause? Is there another set of bearings somewhere in the front end?

Thanks,

TC

 

Are you sure its the front ? Rear bearings on the outboard are very similar to the front and life expectancy is about right.

 

You have a differential in the front that has oil, gears, bearings & seals first check the oil then the U-joints after that a very close inspection. I have Two 2005 Explorers and both had to have seals & bearing (Not a Must on Bearings ??) at around 150K. The original Differential axil seals are of poor design and are subject to fail the replacement is a two piece seal which is great.

 

I'm having the same problem on my 2006 explorer with 60,550. The sound I here is at 40mph coasting. Then at 35 mph I still here it, then at 30 mph its gone. Turn wheel to the right and the left same humming noise. This noise is in the front end I'm sure. New bearings, tire rotated. Oil in the front differential. U-joints look and feel OK no extra play. Would a axle make a clicking sound? Thanks for helping.

 

There is at least 5 moving parts between the differential and the wheel also make sure the rubber boots 4 total on each are not damaged with grease loss. With a 4 wheel drive it is just like having Two rear ends on these Explorers. Front & Back!

 

When worn out, the CV joints will often make a clicking noise that is quite pronounced while cornering. As Weross says, have a look at the CV boots for signs of grease leaking. They will be pretty dirty if they are leaking. I have checked those joints by putting a chain wrench around the axle to hold it steady while twisting the wheel. If you can see movement in the joint with the axle held still, it is an indication of a bad joint.

Right now I am experiencing an oscillating noise on the front axle that I am trying to resolve, but it does not appear to be the CV joints, or the front wheel bearings. I fear something more sinister!

Good luck with yours

 

The noise was there before the tires were replaced? If not, could have a defective tire....feel for a lump on the tread surface.

 

I just open the front differential. it was clean and gears look great. I put in Wal-Mart Supertech semi synthetic 75W90. I have rotated the tires earlier and look and felt the treads no problems. No change in the noise or noise moving to the rear. Took the Explorer for a test drive and the noise has change to a lower humming sound. Not as pronounce but there. I think its pointing to the differential. I'll keep you posted.

 

After dropping the differential out the problem is carrier bearing driver side. The bearing is pitted and rough. Going to replace both sides.

 

The correct oil for these Explorers differential is 75W180. I have done this several times and always change inner and outer bearings and seals. The seals should never need replacing again unless damaged. One thing that can really be a heart breaker is the shims they affect the pinion gear adjustment if this is not correct you only think you have heard Noise. It does not seem to cause any wear if not correctly set when you take it apart all this stuff moves. One major problem we can do little about is the fact that the Differentials are connected to the frame of the vehicle which means any sound there is Everywhere!

 

the new oil is 75 w 140 full synthetic for the rear. IT is still acceptable to use 80w-90 gear lube in the front, but many guys are changing to the 752-140 in the front also.

 

I know most of you think I am full of smoke but just for the record let me give you a line up all of these units have had or now have over 200K on them.

I have owned or own & maintain the following with Manuals:
92 Explorer 4 Door
94 Explorer 4 Door
95 Explorer 4 Door
98 Explorer 4 Door
2000 Explorer 4 Door
2002 Explorer 4 Door
2 Ea. 2005 Explorers 4 Door
2001 F-450 7.3
2003 F-150 5.4
2011 F-150 6.2
That is my smoke!