Hello!

I'm new to ford-trucks.com and I have a question about the 4WD system on my "new" 1999 Explorer.
I just got it yesterday. I traded-in my 1996 Oldsmobile.

Anyway, as I was driving it home last night, I noticed a high pitched squealing noise every so often. It sounded very much like the sound my old '92 Explorer made when I left the hubs locked in on dry pavement. I checked the **** on the dash (shift on the fly) it was in 4x4 AUTO. According to the owners manual, that's the way it is supposed to be during daily driving.

My question is: Is this sound normal, or do I need to have this looked at?
Thank you!

 

Maybe this?
TSB Article No.01-11-4
NOISE—“SQUEALING” OR “WHISTLING” NOISE
FROM FRONT AXLE AREA—DRIVING AT SPEEDS
OF 16-64 KM/H (10-40 MPH)—4X4 VEHICLES
ONLY—REVISED FRONT OUTER HALFSHAFT
DUST SEALS
• FRONT AXLE—“SQUEALING” OR “WHISTLING”
NOISE FROM FRONT AXLE AREA—DRIVING AT
SPEEDS OF 16-64 KM/H (10-40 MPH)—4X4
VEHICLES ONLY—REVISED FRONT OUTER
HALFSHAFT DUST SEALS
FORD: 1998-2001 EXPLORER
2000-2001 RANGER
2001 EXPLORER SPORT TRAC, EXPLORER SPORT
MERCURY: 1998-2001 MOUNTAINEER

Some 4X4 vehicles may exhibit a high-pitched
“squeal” or “whistle” type noise from the front of the
vehicle at speeds from 16 to 64 km/h (10 to 40
mph). This noise may be caused by the front
halfshaft excluder (dust) seals as they
rotate against the inner front hubs. The noise may
be more pronounced in cold weather conditions.

ACTION
Install new front halfshaft excluder seals on each side of the vehicle.

 

Thanks! I hope that takes care of it.
It sounds like the 4WD is engaged all the time. On the ****/switch (shift on the fly) that controls the 4WD, is it posible for the 4WD to be engaged even when it is in AUTO mode?

 

You'd know it. The drivetrain winds up, clunks, chirps etc pretty bad. I have a '98 and the babysitter called me one day saying it was running bad. She hadn't noticed the switch was on 4x4 Hi.

In automatic, you can feel it kick in if you are in tune with such things. I had it on some mush snow/ice and could not tell when it engaged. In the wet or if you gas it around a corner you can feel it pretty good.

 

So, what you're saying is just to forget about it, and that in AUTO mode, it just makes that noise? To me, that just doesn't make sense.

 

Dust seals/hubs always turning methinks. I think I remember the dealer doing this on mine. I don't recall it making the noise though.....

 

Ok, thanks!

Is it going to hurt anything if I leave it the way it is for the time being? (I don't have any more money)

 

From the service DVD description of operation:
C-Trac Function

The C-Trac transfer case transmits torque to the front wheels through an electromechanical clutch assembly. In the Auto mode, while at rest and under cruising conditions, the Generic Electronic Module (GEM) activates the transfer case clutch at a minimum level. This allows for the slight difference between the front and rear driveshafts which occurs normally when negotiating a corner on dry pavement. Under any of the following conditions, the GEM will increase the torque sent through the clutch to the front wheels in order to prevent or control slip.

Slip is detected (by monitoring the Hall Effect Sensors in the transfer case)
Heavy acceleration (by using the throttle position signal from the EEC)
Very light or zero throttle at speeds above 64 km/h (40 mph) (using the throttle position signal from the EEC)
Range Function

In the 4WD Low Range, the transfer case electromechanical clutch locks the front and rear driveshafts for maximum 4WD traction. The transfer case motor also rotates the shift cam to move the reduction fork to the 4WD low range position. This low range shift is accomplished through a planetary gear set which changes the torque to the driveshaft from 1:1 to 2.48:1 ratio.

In the 4WD High Range, the GEM locks the front and the rear driveshafts for maximum 4WD traction. This position is not meant for use on dry or merely wet pavement. It is intended for off-road or severe winter weather use only.

With control-trac the fronts are always powered at least 15%. There should be no noise caused by this. The TSB for dust seals is more for driver annoyance factor than anything else. It should not cause any failure if you let it go.

 

Thanks. I think for the time being I'm just going to leave it alone.

 

EF,
You mentioned in your opening comments about locking hubs on a 92 Explorer.
I have a 92 Explorer and it does not have locking hubs.
Did some have them ??

 

No, they came with Auto hubs, owners changed them out when the Auto's failed due to lack of proper and timely maintenance and cost $$$$ to replace.

 

Yes, these didn't look like OEM hubs.