Have an 2002 Excursion V-10 4x4 all stock, 146000 miles, no mods even stock size tires, 430 gears LS. I have a noise coming from the rear end that I'm trying to fix myself. While driving in 2wd a slight rumble will start at around 45-50 MPH. At 65 it's a more of a growl with vibration that gets worse with more speed. If I let off the throttle a little the noise decreases slightly. But vibration doesn't change. I bought the rig this way cheap.

What's been done so far.
Drive shaft balanced and new joints, It has double u-joint in front and single in back. No change.
Brakes are all new front and rear, calibers and pads. backed the emergency brakes off. No change.
Changed both rear wheel bearing, both sides. No Change.
Pulled diff cover inspected. Few metal shavings very few. Thought there would be more for mileage. Changed fluid, Royal Purple drove around LS seems like it's working fine. No Change.
Gears "looked" fine. Pinion tight no play, no leaks.

So what am I missing?? Been reading whatever I can find online but it's all over. I'm thinking carrier bearings being the pinion is tight. But I would greatly appreciate any help before "throwing" more money away on a guess. Thanks for any help.

 

Have to ask, has that excursion been in an accident ?

Reason I ask is one of my captains purchased a F250 for work and had similar issue. He took my advise and took it to Ford, they found that the entire axle had shifted a little from what looked to be a previous accident.

Are you sure the noise isn't coming from the tranny?

 

Yeah, it's a salvage title. But it drives straight down the road. Tires are wearing just fine. I have 17 years as a frame/ auto body tech and the rig has not had any frame or major structural damage. I never thought about it but maybe the axle did get shifted. Have seen a axle centering pin get sheared off in accidents before. I'll have to check and see if the axle isn't sitting crooked in the frame binding the shaft. Thanks, hadn't thought about that.

 

Good to hear you have the experience in that field...

 

When troubleshot a NVH, the first thing I personally do is to have the wheels rebalanced. More times then not the issue is in the tire or rim.

I had somebody insist that the wheel can not be the problem because they where new, Seems they hit a curb and bent a rim after the NEW tires where installed and didn't know it, musta been when the wife had the car. LOL

 

Wheel base is 15mm or about half inch short on passenger side compared to drivers. I'll check things out and post the results.

I've swapped tires font to rear with no change. I'm sure I'd feel a out of balance tire in the steering wheel if it was that bad.

 

Could be enough to cause it, please keep us updated and good luck with it.

 

Got her jacked up and checked out the rear axle. Axle is actually within spec as being square in the frame. Measures 1/8 inch difference when measured to frame. I suppose the front wheels were turned just a little to throw off my first wheelbase measurement. So I'm still "guessing" carrier bearing.

 

I would be taking a close look at the double cardin ujoint set up.

To my knowledge excursions did not come with them. The rearend is not automatically set up for them. If you have that setup the rear axle needs to be tilted up to put the yoke in line with the output shaft of trans/transfer case.

I.E. check for proper driveshaft geometry, for your setup.

 

Thought I'd give an update. Finally tore the rear end apart. Bad carrier bearings like I thought. Bearing and races about destroyed, pinion damaged. That's what I get for buying a salvage rig.

But after replacing all the bearings, both pinion, both carrier and wheel. Put in a new Yukon ring and pinion. Set pinion at 30 inch pounds and back lash at 14 thousands. Seems to be some difference on back lash at 6-10 thousands or 12-16 thousands depending on source of info.

Now the rear axle has a very noticeable whine at 55mph under light acceleration. Nothing on decel. Now what?? Back lash could be wrong but who really knows?? I can live with the noise but I don't want to destroy nearly $1000 worth of parts. Only have about 30 miles on it. So it's far from being broken in. Suggestions????

 

I don't have anything positive to add to this one. I'm trying to figure out what's next on my Ex as well since my symptoms are almost exactly as yours were.