2002 Expedition, XLT, 4x4, 5.4L, 115,000 miles

Good evening all. I have been browsing the forum for years and scoured the boards for this topic, but it was time to finally join and ask for help when I couldn't resolve my problem.

I have been chasing a vibration for the last year/7,000 miles:

Description of the Vibration:
- The vibration is more of a low grade rumble felt predominantly in the seat, and to a lesser extent in the steering wheel.
-- The steering wheel does not shimmy, however, like an unbalanced wheel/tire.
- It is barely audible as a low ruble/hum, but no grinding/clunking/squealing sounds are evident.
- Most significantly, the vibration is intermittent. Some days, the truck drives smooth with no unusual vibrations at all. Some days, like today, the vibration is present during one drive and absent 1/2 hour later on another drive. Sometimes the vibration goes away entirely during the drive or comes up when no vibration was present before that.
- It seems to be less common when the outside air temperature is cold - sub 40's. But this isn't always true.
- Vibration occurs most notably between 45-65mph but does continue at higher speeds - I just don't find myself much above 55mph during my 10 mile commute to base. <45mph, it's smooth or so minor as to seem absent.
- When I let off the gas on a steep enough downhill to maintain speed, sometimes the rumble intensity (not rate/frequency) actually seems to slightly increase.
-- The rate/frequency increases with increase in speed and decreases with a decrease in speed until dropping off entirely at 40-45mph.
- If I put the transmission in neutral when the rumble/vibration is occurring, the rumble/vibration continues with the same intensity and frequency even with engine now at idle RPM - so it doesn't seem like an engine issue. Of course, as the truck slows while in neutral, the vibration slows with speed. I will check the motor mounts tomorrow on the lift.
- The front rotors and pads are new and not warped; there is no evidence of pulsing brakes. Brake application is smooth and quiet.
- The vibration might subside slightly in turns, but I'm not taking big turns at 45+mph, so it's hard to be sure. This might just be wishful thinking too.

(Failed) Attempts to fix the Vibration:
- Downloaded the computer - no codes
- New Tires <3000 miles ago. There is no cupping, feathering, or other unusual wear. = no change to vibration
- Tires have been dynamically balanced & rotated twice in last 500 miles to attempt to isolate the vibration = no change to vibration
- Aligned the front end = no change to vibration
- Replaced a failed coil pack = no change to vibration
- Changed plugs <1000 miles ago = no change to vibration
- Transmission rebuilt <300 miles ago (Torque Converter failed - metal shavings in transmission) = no change to vibration (but acceleration is better and shifts much smoother, especially at torque lockup, which was really bad)
- There does not appear to be any play in the hubs, though I have not yet removed the wheels to check = I have only rocked the wheels while parked.
- Pulling on the suspension components does not reveal any play out of the ordinary.
- I have not checked universal joints yet; that is also on the list for tomorrow.

Ok, I can't think of anything more. I've written too much already; apologies for the many words above. I'm simply trying to preempt the questions resulting from too little info provided. Yet, I'm sure I missed something.

I love my Expedition! It is still beautiful inside and out and look forward to many more years together. I'm open to any and all thoughts. You guys rock!

Thanks and blessings from an active duty Air Force dude,
Bob

 

You might wanna check Your u-joints and maybe axle bearings and your hubs could be going. Those are a few things I would check.

 

A second vote for U joints . I am a little disappointed that the transmission shop did not catch them if they are in fact bad.

 

Take a look at your exhaust hangers. I had a vibration when my truck was only a year or so old and it drove the dealer nuts until they replace some hangers in the exhaust system.

 

Thanks for the awesome replies.

Great idea to look at the exhaust hangers. Another buddy recommended looking at the roof rack. Checked both--and both are solid. But it was a great idea.

There is no noticeable play in the u-joints, but perhaps the lubrication has dried up - they are original. Bummer about no grease fittings.

My plan is to have the U-joints replaced first, then move on to the hubs (which I might do myself), and if that doesn't work, look to the rear end (which shows no signs of leaking). Logical order/plan?

Could this be related to the transfer case even though it's in 2WD (AWD) when driving?

Any concerns or recommendations with the hubs below?

List: Wheel Hub Assembly - 2002 Ford Expedition | O'Reilly Auto Parts

Wheel Bearing/Hub Assembly-Front | 2002 Ford Expedition 4WD 8 Cylinders L 5.4L EFI | AutoZone.com

 

This type of reverse driveline pressure test usually indicates a change in the pinion angle in the rear differential if the intensity increase like you described. This vibration can be a simple matter of worn pinion bearings, or if by chance someone replaced the pinion seal on the rear end and didn't tighten the center bolt correctly.

 

Great input! Thanks. No work has been done to the rear end. So perhaps it's the pinion bearings, as you note.

I made the statement about the rear end in the previous post "shows no signs of leaking" based on no staining at all in the garage or on the driveway. But a quick inspection of the rear end shows an obvious leak - what a dope. It's not dripping, but there is obvious evidence of a leak. (see pictures)

Pictures: photobucket.com/battman_expedition

 

Check the fluid level in the rear end, maybe you'll get lucky and find that it is just low. If it is real low you might want to try changing it before tearing everything apart.

 

I'm going to be out of the country for the next two weeks but when I return I will do the following (in this order) and see if I can't isolate the issue:

- Replace rear differential fluid
. -- I can't locate a 12 bolt gasket online...just use RTV??
- Replace front differential fluid
- Replace U-Joints - no noticeable play but...
- Replace front hubs - no noticeable play but...

Reasonable plan?

Thanks to all!

 

Sounds like a plan to me. I saw your first post last week and now my truck is doing something similar. It sounds more like a suspension part rattle somewhere in the rear end. Climbing under tomorrow!

 

Yes, just use RTV.

 

Thought. Does this model have the rotting trailing arms which can lead to pinion angle?

 

FYI. Mine ended up being the rear axle bearings (left is worse than the right). I jacked the rear end off the ground and supported it on jackstands, then put a long bar under the rear tires one at a time and lifted them up. Sure enough that was my heavy rattling noise, and there is play in the axle bearings. I will tackle this next weekend and take pictures.

Thanks.

 

interesting post.. I have a 2004 Expy, and I have a very minor vibration after 75 mph. it's in the workshop now to install the S spring in the front diff, and we found out the S spring is already there !!

I can't figure out what's wrong since everything we checked is ok !! brakes, U joints, tires, shocks, all ok ..!!

 

I'm back from Africa. Dropped the truck at the dealer. Apparently my ability to notice this subtle vibration exceeds theirs. Three people drove it, twice with me in the car. They could not feel the vibration I was describing - despite it happening while we drove. They jacked it up and inspected the suspension, removed the drive shaft and checked the u-joints, checked the bearings/hubs, etc. All were good. They "raised the white flag" (their words), charged me $5 for their time, and sent me home.

I plan to change the rear diff fluid this weekend. They wanted $139 for the service but that included sucking out the old and replacing it with new fluid. Removing and replacing the rear diff cover then refilling was quoted at $259. No thanks.

Back to the drawing board.