03 XLT AWD front end howl and clunk....

[vacsplorer]

I am new to the forum and I have searched all front end Q/A's and can't find identicle problem.

I have a 2003 Exploder XLT AWD that has a very weird problem with what I am guessing front end issues. At about 35-40 mph to around 65-70 mph I get a pulsing howl and thump felt on the steering wheel and floor board when I let off the gas. It is also intermittent in AUTO 4X4. I then tried it cruising through the streets, and noticed it is a constant and louder pulsing whine and thump when I select it in 4x4 HIGH. Then when I select AUTO 4x4, it's a little quieter whine/howl and less noticable thump/clunk and it only happens when I DO NOT push on the gas.

Any guidance???

 

[Elwood]

I have a 2004 E.B. V8. I have had all of the wheel bearings replaced because of noises and vibrations. Come to find out wheel bearings are a big problem with these Explorers. I would look there first.

 

[vacsplorer]

I did the shake/wobble test once the ford was on jacks, and there is no wobble in either front wheel. I took out both fuses for 4X4 and took it out again. The 4X4 HIGH and LOW lights blinked intermittently (as I figured they would) and the howl and bump was gone. I placed one fuse in, and took it out again, no noise or bump, Then I reinstalled second one in and I only got it to do it once. I selected HIGH and it engaged, then AUTO and it disengaged. Still no noise. I also pulled out and inserted the grey and black plug on the bottom of the 4X4 controller behind the glove box. Still no problem....

Does anyone know or have the electrical schematic for these fuses and related circuits? They were fuses 17 and 18 in the engine compartment. Any info would be great. Let you know if the problem comes back. Thanks.

 

[windsorman707]

Sounds like a loose nut behind the wheel.

 

[kramer_79]

I have the same truck and the same problem, I just bought it 2 months ago and the guy I bought it from said he had just done the front bearings. I changed the rears this weekend and still the whine and thump continue. I'd really appreciate any advice.

 

[gtyates]

Have you tried having the differential fluids and transfer case fluid changed? Might help?? Doing this took care of some low speed bidning I was getting in mine.

 

[abbyroadkill]

Have you tried having the differential fluids and transfer case fluid changed? Might help?? Doing this took care of some low speed bidning I was getting in mine.

mine was front diff fluid. it was leaking

i got an '03 AWD and the noises were similar, i think

it also would grab when i turned sharply at parking lot speeds

 

[3ngin33r]

Front differential

I had the same problem; I noticed some leaking under the front of my truck. I thought I needed to replace my oil pan gasket. Turns out I went around a corner real hard and broke my differential casing. Now it is really leaking, and I have a hard clunk under my feet once in awhile. I found a used one on ebay through Nordstroms for $250 and the guy at the shop said about $200 to replace it. Hoping that fixes everything! The dealer quoted me $3000 for a new on installed...LOL

 

[oldgeez]

04 Front end shudder

When I let off the gas in my '04 Explorer I get a cyclical shudder...kind of a thud, thud, thud. You can feel it in the floorboard as well as the steering. A post by VACSPLORER had the same problem and he/she removed fuses 17 and 18 and it went away. (His/Her problem stayed "gone" after reinstalling the fuses).

I've removed the same fuses and it does go away. But when I reinstall the fuses it comes back. It would appear that it is not strictly mechanical since it goes away when the fuses are removed.

I have replaced both of the front hubs within the past month (it was doing it before and still does it). 85,000 miles.

Any help is appreciated.

thanks,
Oldgeez

 

[imp]

....... I then tried it cruising through the streets, and noticed it is a constant and louder pulsing whine and thump when I select it in 4x4 HIGH.
Any guidance???

Well, if your streets are paved, and yer cruisin' around on 'em in 4X4 HIGH, there will be a quick increase in the noises yer experiencing! imp

 

[imp]

When I let off the gas in my '04 Explorer I get a cyclical shudder...kind of a thud, thud, thud. You can feel it in the floorboard as well as the steering. A post by VACSPLORER had the same problem and he/she removed fuses 17 and 18 and it went away. (His/Her problem stayed "gone" after reinstalling the fuses).

I've removed the same fuses and it does go away. But when I reinstall the fuses it comes back. It would appear that it is not strictly mechanical since it goes away when the fuses are removed.

I have replaced both of the front hubs within the past month (it was doing it before and still does it). 85,000 miles.

Any help is appreciated.

thanks,
Oldgeez

OK, geezer, I looked some things up, but have no clue yet if it can help or not; (assuming 4.0L eng. here). F-17 feeds power to ONLY the Transfer Case High to Low Relay, located in the Engine Compartment Relay Box. F-18 is used ONLY in 4X4 veh., and feeds that portion of circuitry controlled by PCM feeding the Accelerator Pedal Position Sensor.

Not clear what is going on; can you relate the complaint in any way to interruption of these functions? My guess would be that killing the Acc. Ped. Pos. Sens. would result in a "no-drive" condition. imp

EDIT: Ah, lightbulb maybe! These trans. are set up to allow PCM to change shift patterns from normal (High Range) when in Low Range. So, proly F-18 is in use ONLY in Low Range. It is beginning to sound like the Transfer Case drive motor Position Sensing is out of whack. Will try to research this more. Wonder who/how suggestion to remove these fuses came about?

2nd, EDIT: FYI, they want the gas pedal to be less sensitive in Low Range, so guys don't go jerking driveshafts out of the trucks! So pedal must move further to effect movement of drive-by-wire motor.

 

[The Rainmayker]

EDIT: Ah, lightbulb maybe! These trans. are set up to allow PCM to change shift patterns from normal (High Range) when in Low Range. So, proly F-18 is in use ONLY in Low Range.

This sounds very likely! If only vacsplorer would re-visit this thread and let us know what was found. I love unusual challenges like this!

 

[Todd~Rod]

check the fluid level in the front differential

 

[oldgeez]

I have the explorer today so I can try putting in one fuse at a time to try to narrow it down. The differential is full.

And as mentioned, it would be nice if vacsplorer returned...I sent him/her a private message a while ago, but no response.

thanks for the info....I will advise.

 

[oldgeez]

I looked around under the truck and couldn't see anything obvious. I replaced fuse 18 and problem did not go away. Removed fuse 18 and replaced 17 and problem stayed away. So, it appears that whatever fuse 18 controls is where the problem is.

So with fuse 18 out, shudder is gone, the 4x4 low light is on, but it is not in 4x4 low.

Don't know what to do at this point. I don't want to start replacing things without a serious plan.

Thanks.

 

[imp]

I looked around under the truck and couldn't see anything obvious. I replaced fuse 18 and problem did not go away. Removed fuse 18 and replaced 17 and problem stayed away. So, it appears that whatever fuse 18 controls is where the problem is.

So with fuse 18 out, shudder is gone, the 4x4 low light is on, but it is not in 4x4 low.

Don't know what to do at this point. I don't want to start replacing things without a serious plan.

Thanks.

Fuse 18 supplies power to that part of the computer and associated hardware to allow it to use an altered shift strategy when in 4X4 LOW Range only. Fuse 17 feeds power to the transfer case shifting mechanism (drive motor) which shifts the case into Low Range. So my guess is, the shift motor is attempting to shift into Low Range while driving in 4X4 AUTO or 4X4 HIGH, due to maladjustment/fault with shift motor, but this is only one of several possible causes, including as problem with the computer itself, which might not throw a trouble code.

Therefore, you will do no harm, IMO, to the vehicle by leaving fuse 18 OUT, and you will be unable at the same time, to use 4X4 LOW (there will be none). However, it would be comforting to know that 4X4 HIGH is operable; this can be checked on some soft unpaved area, preferably with a confederate standing by to observe that the front wheels are being powered when the vehicle is accelerated suddenly from a standstill, enough to slightly spin the rear wheels. imp

 

[oldgeez]

OK...current status...shudder is gone with fuse 18 back in.

Rightly or wrongly, this is what I did....since there is mercon in the transfer case, I added a tube of 'dr. tranny instant shudder fix' to it (napa), and I added "limited slip additive" (napa) to the front differential, both made by Lubegard. Before driving I pressed button to put into 4 wheel low and moved it backward and forward 10 ft., then the same with 4 wheel high. Back to 4 wheel auto and road tested and shudder is gone.

A week or so ago when this started I did put it in 4 wheel low, but I don't remember if I moved the truck forward or backward then or not.

As imp pointed out, it would go into 4 wheel high without the fuse and driving in 4 wheel auto for the past week or so did not seem to hurt anything.

Unfortunately, I don't know what fixed it...the additives, or the moving into 4 wheel low and then high and driving a few feet. But, it's fixed for now. Wife will be the ultimate test.

Thanks all for the help and information.

 

[imp]

Please keep us informed regarding any return of the problem. It is possible, though IMO I think improbable, the "stuff" added to the transfer case freed- up a sticking condition which was causing incomplete movement of the shifting mechanism. That may have given the PCM erroneous info that the transfer case was in low range, which would call for altered shift schedules.

imp