I developed a strange grinding/rubbing noise yesterday. It seems to happen only for the first 5 miles or so when the drivetrain is cold or cooled down, and only below 40mph or so. It could be that there is enough road noise above that level that I can't hear the grind anymore. It also seems relevant to wheel speed and only happens when I make a right turn. Hard to describe, but it is a brief grind/rubbing sound, then goes away until the time comes around again, and I can feel it in the floorboard under my feet. Best way to describe the briefness, is, say, when the wheel valve stem is at 12 o'clock I feel/hear the grind, then it goes away until the stem reaches 12 o'clock again, then disappears until it comes around again. I don't know exactly where the valve stem is, but just trying to give an idea of the briefness of the noise. Hope that makes some sense. I checked the lug nuts on the left front wheel and they're all tight. I see no signs of rubbing anywhere. The front brakes were done 3 months ago, so I doubt it's a bearing. It's just odd that the sound goes away once things are warmed up. Anyone have any similar experience or have a clue what it might be? Expedition goes in for annual State Inspection on Tuesday. Thanks!

 

Do you have the LSD rear end? I'd guess it is that. $80 in fluid and friction modifier will set it right. I know you said it feels like it is in the floor boards, but I've been through this a few times swearing it was the front end but in the end it was the rears.

 

Yes, I do have the rear LSD. I was starting to think something with the front differential, but hadn't given the rear one a thought, since it feels like it's from the front end. I've learned over time how sound and vibrations can travel throughout a vehicle via the drivetrain and point you in the wrong direction to a solution. Thanks for the advice. Fluid is supposed to be changed at 100k anyway, correct? I'm past that point on the original fluid.

This is just one of the many reasons I love this site. Lots of people having similar experiences, leading you in the right direction to a solution! Thanks again.

 

I wound up doing the rear (with one modifier), the T case, and the front diff only to wind up back at the rear again. My Ford dealer looked at it after I was stumped and put a second bottle of modifier in the rear, problem solved. They said they always double up on the rear modifiers and never have any trouble.

 

Good info to know. Thanks. As for doing the change (I haven't crawled underneath yet), but is there a drain plug on the Expedition's axle or do I need to pull the cover off, therefore needing a new gasket, etc.?

 

Not sure on the 02, on my 03 and 04 it is fill and drain plugs.

 

I would now say it's definitely coming from the rear of the Expedition. I had a full vehicle of people yesterday, with my girlfriend's son way in the back in the 3rd row seat. He said the sound & noise is very noticable and much more prominent under his feet when the Expy's moving in the back seat than it was up front. Going to get the fluid & friction modifier tomorrow and hopefully do the fluid swap tomorrow night. I'll let you know how I make out and if that solves the problem. Thanks again for your help so far.

 

30 minute ride tonight and the noise is becoming very noticable and not just when turning right anymore. I can feel/hear it when going straight down the road now and the ever so slightest turn to the right. It sounds like when your brakes need replaced - that rumbling & grinding sound. Left turns I can barely hear it. When I got home, I crawled underneath again and the rear diff cover is a little damp in a section. I pulled the fluid level plug on the differential to look inside (what a chore that was while lying on my back on a blacktop driveway) and the mechanicals inside looked like they had plenty of lubrication. The fluid level was a little below the plug hole. I didn't have any modifier on hand, so topped off with about 1/2 a quart of gear lube and reinstalled the plug. I took the Expy back out on the road and the noise was non-existent for about 1/2 mile, but then re-appeared. The plug did have some metal slivers on the magnetic part. Is that normal? I suppose after 105k miles, there is bound to be some wear. Hopefully our lift at work is available after hours tomorrow night so I can tackle this and hopefully cure this annoying noise.

 

Was the gear lube you used for LSD's? Sounds like things might not be going so well for you. I'd do the full change with modifier asap, but with shavings it might be too far gone.

 

Driving to work this morning wasn't bad at all. Hardly heard the noise the entire 45 minute ride, except when making right turns, and even then, it wasn't as noisy as it has been. I talked to our mechanic at the shop this morning about it (he's a Chevy guy but very resourceful in all areas) and he thinks it's the gear fluid needing changed, as well. Also said it may be an axle bearing, but to try the fluid swap first.

The metal slivers I found on the drain plug weren't chunks of metal, but those little spiny slivers, like a splinter-size that gets stuck in your finger and a PITA to get out without microscopic tweezers. Our mechanic said that is nornal to see. Expedition goes in the shop tomorrow for annual state inspection. I'm going to have them look at it and see what's going on.

 

to drain the rear diff on my 2000 you have to remove the cover. I just encountered the same noise and am pretty sure it is coming because of low fluid in the diff. I have a leaking pinion seal. I will be sure to add a second bottle of modifier also. good luck. fitzy67

 

Well, I don't have the Expedition back yet, as it's still in the shop, but I do have a diagnosis on the noise.

Annual State Inspection went well. Only issue was the rear brakes which needed replaced after 105,000+ miles. Yes, they were the original brakes from 2002. Diagnosing the noise took some effort on their part, but after the owner of the business and his lead tech took the Expy out for a test ride individually, they both returned with the same finding. The rear differential is fine; nothing wrong with it. They pulled the cover and everything looks great, they said. The noise is the right front hub bearing assembly. The owner said the bearing is shot and the hub sustained some damage, as well, so the entire assembly has to be replaced. Joy, joy.

So, I'm glad I don't need a new rear differential or an axle bearing job done, but it's going to be an expensive bill when it's all said and done, including the rear brakes (rotors, too) and state inspection costs. At least the Expy will be 100% again and ready for the winter and ensuring myself and those I have as passengers will be riding in a safe vehicle. That's how I am looking at the bright side of this. It's been an awesome truck, so I can't really complain about a major repair like this.

 

Good news for the diff, bad news for your wallet. My 04 has original brakes front and rear at 60k. My 03 needs fronts every 25k, rears every 50.

 

Yes, very good news about the differential, but I can feel my back pocket floating already and I haven't picked the Expy up yet. The shop called me a bit ago and said it's all done. I cringed when I asked what the total bill was. I really think he's cutting me a break, as the total is less than what he said it would be yesterday afternoon, but still a major ouch. Plus, the owner stayed late last night to keep working on it. Shop is only open until 4pm, but he stayed until 7pm. I've been taking my vehicles to them for longer than I can remember and they've always treated me well and I've never had an issue with their work. Top notch quality and I've referred other people/friends to them, as well, and they've thanked me for recommending this shop to them.

 

I know this problem was several months ago, but I'm curious about something. Did you happen to notice a squeak in the front wheel a while before you heard the grinding? I've got an '03 Navigator with 74k miles. I've got a squeak a low speeds, especially when I brake to a stop and then start forward again. Mechanic recommended replacing the front hub bearing and the bearing assembly. I'm wondering how long I have until I get to where you were.

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2003 Lincoln Navigator, 5.4L DOHC V8
74,000