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'97 Control Trac Problem--Won't Disengage 4WD

I have a 1997 Control Trac 4.0L OHV with about 130,000 miles on it.

With the selector set on Auto (choices are Auto, 4H and 4L) 4WD is engaged all the time. This is based upon the fact that it's clumping while turning, even on hard dirt (almost new Michelin LTX tires). I did the 'ol clean the transfer case sensors trick and it didn't help. I think the transfer case clutch is engaged all the time but I cannot find a description of the TC clutch either in my Hayne's manual, online, or in my Ford Service Manual on CD. The Ford manual doesn't seem to have this particular problem listed under their diagnostic procedures.

My understanding is that the front differential on the vehicle is a regular "live"open differential and there are no locking hubs. Is this correct? That might explain why one front wheel was spinning while attempting a steep, muddy hill. This kinda stinks if this is the case. Maybe it's time to trade it in on a first generation Explorer.

I removed the servo motor to get to one of the sensors and noticed that the TC choices are H, L, and N. On the 91-94s the choices are 2H, 2L, and 4L. I could not find a position where 4WD was not engaged.

The rear seal on the transfer case is leaking. The fluid looks rather dark. Is it possible that the fluid was contanimated through a minor leak in the seal? Could this be causing the sensors to not work at all? I changed the TC fluid 25,000 miles ago or thereabouts. I suspect that new fluid would probably become dirty soon so is there such a thing as flushing a transfer case? Of course a new seal is imperative.

There is a minor to moderate whine from somewhere around the middle to the front of the vehicle that is constant at a constant speed. It does not change while accelerating/decelerating. There is a slight clunk when coming to a stop, either in D or R. If it had radius arms I'd think it needed new bushings. I've read a lot about replacing ball joints but don't recall the symptoms. Is clunking a sign of bad ball joints, or perhaps bad CV joints? Could worn wheel bearings somehow cause the Contro Trac to go wacky? Or is this whine somehow related to the transfer case problem?

I disconnected the wiring going to the transfer case and 4WD is now disengaged. Is there any problem with driving it with the TC wires disconnected? I've read about the "brown wire" but that wouldn't really fix the problem--it would just make it go away.

I'm going to try to get the codes read but this car is not here most of the time (daughter's car) and unless she crawls underneath and reconnects the TC wiring before getting them read I suspect the code info would be erroneous.

Reply to
Ulysses
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Reply to
Kenneth J. Harris

Yes, I want it to be disengaged when turning on pavement and hard dirt etc. It *used* to work now apparently the electromagnet clutch inside the transfer case is engaged all the time. At least that's what seems to be the problem. If I don't fix it I fear that other things in the front are going to break. My older Explorers have a 2WD setting. When Control Trac works it seems to work quite well (according to my daughters who says she almost never has to turn the switch no matter how bad the road is).

I have found many posts about disconnecting the "Brown Wire" that activates the TC clutch but the only thing I've found so far about actually fixing it is to clean the sensors. I gather that (other than the clutch problem) many of the guys who do the brown wire trick just want to be able to leave major portions of their rear tires on the pavement. Somebody else must be paying for them.

Reply to
Ulysses

Just for posterity, the transfer case rear output seal was leaking. I finally managed to get all the stuff together and replaced it yesterday. With no leaks and new ATF the Control Trac now seems to work properly again. I did clean the upper sensor again because it was easy to get to. The old fluid was a bit dark but still transparent. It was low on fluid and I had been checking it regularly and filling it as needed but the leak must have suddenly gotten worse. BTW you need a 30mm thinwall socket to remove the yoke nut from the transfer case--a regular socket will not fit inside the flange.

I have also been told that the front ABS sensors might have an effect upon the Control Trac system. My ABS light was not on and seemed to be functioning properly but if the new fluid and seal didn't work that seemed to be the next thing to look at.

Reply to
Ulysses

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