Chasing Intermittent Vibration/Rumble - 2002 Expedition

[battmanf16]

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

Chasing a vibration for the last year/7,000 miles:

Description of the Vibration:
- The vibration is a low grade rumble felt predominantly in the seat, and to a lesser extent in the steering wheel.
-- The steering wheel does not shimmy like an unbalanced wheel/tire would cause.
- 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, comes and goes during the same drive.
- 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 increase slightly.
-- 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.
- 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
- 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.

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

 

[walnuts4x4]

next time you get the vibration I would turn off overdrive and see if that helps... if it does could be a low grade miss from a COP going bad and not tripping the CEL... I had this problem a while back and didn't solve it until I changed all the COPs... not 100% but it might be worth a try.... taking it out of OD will change the power band and cause the COPs to work differently and sometimes can help diagnose the problems... others should chime in.... what AFSC are you? I used to be a 3PO71 = SF

 

[CARO'S98EB]

Sounds like driveline to me. I would ck the wheel bearings/hubs and the u-joints. Is it a 4x4 with AWD? might be in the AWD system.

 

[battmanf16]

next time you get the vibration I would turn off overdrive and see if that helps.... what AFSC are you? I used to be a 3PO71 = SF

Good question. No, turning off OD doesn't change it; it even makes the sound/rumble/vibration in neutral when at speed. I'm leaning towards driveline too. Yes, it's 4x4 w/AWD. I hope it's not the AWD system.

A quick inspection of the rear end shows an obvious leak. It's not dripping, but it is clearly leaking. (see pictures)

Pictures: photobucket.com/battman_expedition

My AFSC is K11F3H - F-16 pilot.

 

[Racenut]

This may shed some light on your problem :

REAR AXLE TSB Link
http://www.justanswer.com/uploads/bkitchener/2009-08-12_162454_axle_noise.pdf

My 2002 Ford Expedition EB and also my sister in laws 2002 Mercury Mountaineer are both suffering from the same problem.

It appears that Ford Motor Company used an inferior metal ring and pinion set ( in the 8.8 and 9.75 axles ) and many vehicles are suffering these symptoms ( The TSB calls for replacement of all bearings, shims and the ring and pinion set it also calls for changing the Rear Diff oil from the Fuel Efficint 75W90 synthetic gear oil to the 75W140 synthetic gear oil ).

If you do a google search you will find that there are many complaints on the same issue and many have had the issue " FIXED " at the dealer only to have them do it over and over again because they keep using crap parts.

It seems that the only true " FIX " for this issue is to do a complete rear axle rebuild with an after market ring and pinion set.

Below is a link to Randy's Ring and Pinion and so far they seem to have the best prices from what I have found on good quality ring and pinion sets such as Yukon Gear.

http://www.ringpinion.com/DiffWizard.aspx

Hope this helps a bit.

 

[walnuts4x4]

what about swapping the entire rear axle with a newer expy rear end with the same gears.... might be cheaper and easier if this is the problem... just my .02

 

[Racenut]

what about swapping the entire rear axle with a newer expy rear end with the same gears.... might be cheaper and easier if this is the problem... just my .02

In order to swap in the rear axle from a newer expy you would need a lot of fab work since he has a '02 with a solid rear axle and in '03 they went to the independent rear suspension. That and it would have to be '06 or newer because the TSB covers from '97-'05.

 

[battmanf16]

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!

 

[CARO'S98EB]

sounds reasonable. when you pull the driveshaft you should be able to tell if the u joints are real bad by moving all around.

 

[catmandu]

Well, crap. And I thought I just had some noisy tires.

 

[Expeditionary]

u joints

 

[catmandu]

Okay, started some troubleshooting on mine: did a drain and fill on the differentials and transfer case, no change. Dropped the tires to 20psi, no change. Pumped them to 45psi, no change. Went to pull the front drive shaft to isolate the axles and HEY those bolts on the transfer case side of the axle sure were easy to get out! No front drive shaft road test, no rumble!

Hmmmmm . . . . funny how the front drive shaft has replacement u-joints and is painted tan.

 

[catmandu]

Well, took a file to the flanges and made them flat and shiny. Bead blasted the bolts to make sure the loc-tite had a good surface to bond to, and then re-installed the front drive shaft.

Correctly.

As in not backwards, like it was (I now know) when I took it off.

Yep, right there in the manual, says to make sure the boot for the slip joint is towards the transfer case. Seems previous owner missed that point when he replaced the u-joints. The flanges are ever-so-slightly different, and that made a difference in how well they fit together. The vibration probably worked the bolts loose, although I highly doubt they had seen a proper torque wrench before.

Good luck, OP, hope yours is as easy and cheap!


Note to self: never talk yourself into an what you think is an obvious answer if it continues to bug you for several thousand miles. (Noisy tires, sheesh!)

 

[battmanf16]

I will look at the front axles. But I'm the only owner and I know they have never been removed. But perhaps the bolts have worked loose.

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 rear 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.

Update: I put the truck on a lift this afternoon. The front drive shaft bolts are tight. No play there.

 

[battmanf16]

Changed the diff fluid today (including friction additive). It looked good (a little dark) and about the right quantity. I will put it on the road tomorrow to see if that helped.

Front diff fluid gets changed this week.

 

[battmanf16]

Front and rear diff fluids changed. Seems [maybe] to have reduced it. But it still happens some.

 

[WSS1]

I am having the same problem on my 01, I changed the diff fluid and did a good flush a month ago and found fines on the plug and flakes in the bottom of the diff housing. I flushed and refilled to find the vibe/howl gone, now it is back and I checked the plug and it has much more fines on it now than when I flushed and filled! Darn.

This will be the second round on this diff. The first went out under warranty so I did not pay much attention.

I have looked into the yukon r&p set and a timken rebuild set. Is it easier to let someone else do it? Maybe even get a warranty out of it for a year or so. I am sure I could tackle it but is it worth it? Has anyone had theirs done? What did it cost?

Any help appreciated!
WSS

PS, GOD bless battmanf16 and all those who have served and are serving our wonderful country!