I just bought a '96 with the 4.0 and an automatic. It is 4x4 and the light on the dash comes on but nothing else seems to happen as far as the engagement. Is there an electric motor to engage the transfer case? Where should I start in troubleshooting the problem. Help always appreciated.

 

Yes, there is a servo motor on the transfer case that moves it into 4WD. These motors (especially on the 91-94s) have a tendency to get stuck. One solution is to tap it gently with a small hammer while the switch is in 4H (or the button is being pushed). But, you probably have Control Trac. It is my understanding that with this system the front axle is always engaged and this degree of engagement varies according to how much difference in speed there is between the front and rear axles. There are supposedly two sensors in the transfer case that can be accessed by removing the servo motor. One is for the front axle, one for the rear. According to what I have read just cleaning these sensors can solve some problems particularly 4WD engagement when it is not required or wanted. If your 4X4 light is on this usually indicates that 4WD is engaged. Does the 4 Low light come on when you turn the switch to 4 Low? You should be able to hear the motor turning when you switch between 2WD and 4WD while stopped. BTW you have to be in Neutral and stopped (or very nearly) to engage 4 Low and to switch back to 4 High or 2WD. You can switch to 4 HIgh at up to around 45 mph but I can't imagine going that fast if conditions are that bad.

Another possible solution is to take apart the motor and clean it or simply replace it. I have had good results cleaning my servos on a '91 and a '92. I will be finding out about the transfer case sensors on Saturday on my '97. I've only heard of one sensor but my Ford shop manual shows two. My daughter said it's in 4WD when it shouldn't be.

The early Explorers had very unreliable locking hubs and many of us replaced them with manual hubs. I've not read/heard of hub problems on the '95s and up. For starters I suggest checking the fluid levels in your front differential and transfer case. The transfer case gets Mercon ATF. The differential gets (might want to double-check this) 85W90 gear oil. One other thing that seems to happen is that the limited slip rear differential gets an oil change but somebody forgets to add the traction additive. The only other thing I can think of is that uneven tire wear can cause the axles to rotate at different speeds but that would make it go into 4WD.

To test my 4WD and rear differential I have a hill that I can't make it up in 2WD. I go as far as I can in 2WD. When the rear tires start spinning I check to see if the holes are about equal. If so the rear differential is locking OK. Then I put it in 4H. If it makes it up the hill then 4WD is working

 

If I've understood correctly, the '96 V6 has three positions: 2H, 4Auto, and 4L.

So which position isn't working, 4A or 4L? What isn't working about it? It isn't sending power to the front?

Many people have had trouble with the front axle disconnect in the differential. It's vacuum actuated, and if the vacuum lines break or something like that, you won't get power through the diff at the front.

 

On the '96 that we had you couldn't hear anything engage. It is equipped with "control track" and most of the time you won't even need the 4x4. If I remember correctly if the 4x4 doesn't engage then the 4x4 light will start blinking because the "hall" sensors won't see the drive shaft turning and will alert you that there is a problem. A simple test is to put it in 4x4 on a gravel road that has a slight hill and then get on the gas pretty hard. If the 4x4 isn't working you will know.

 

We are getting some pretty good snow this afternoon so I took it for a spin to see if anything was engaging. It seems that the 4x4 auto position does nothing but turn the 4x4 light on on the dash. When I try 4x4 low, the dash 4x4 and low light flash a couple of times and neither on stay on. I plan to take the electric transfer case motor off and see if it turns at all. How does the front axle engagement work. Does the vacuum motor move a lever or something? Thanks.

 

i thought the explorers engaged at the transfer cae as mentioned above. the F150 has a vacuum solenoid at the frond differential. im not sure the Explorer has that.

 

From what I understand, '95 and '96 have the vacuum actuator on the front diff, but they did away with it in '97+. I'm not certain exactly how it works (it's probably a lot like the F150 steve(ill) mentioned).

 

Well, like gcosmo said, it turns out you can't hear the servo motor turning the transfer case on the '97 either. At least I couldn't. You sure can on the '91-94s though.

I scoured my Ford service manual on CD yesterday trying to determine if there is a vacuum activator but could find very little information about how the whole thing works. It appears (not confirmed) that there are no locking hubs, at least on the '97 Control Trac), and that the front hubs are always engaged. I read some stuff about Traction Control but I got the impression that it did not apply to the Control Trac models. A lot of interesting stuff about how it controls the air intake and torque and brakes to control slippage etc. but it was unclear which things applied to Control Trac and which didn't. There are a lot of "pinpoint" tests that you could do but my experience with Explorers is that the problem is generally something simple.

As for my problem (going into 4WD when it shouldn't) I cleaned the two sensors. One is easily accessible and the other one you need to remove the servo motor to get at. Both had a slight dark smudge. I also have a seal leak at the rear driveshaft end and it was a bit low on fluid. I filled it with ATF, put it back together, and the problem seems to be gone.

An interesting note: I suspected the IAC valve on my '97 so I was reading about it. It says "the IAC CANNOT BE CLEANED." Oh darn. I guess all of us who have cleaned them didn't really fix the problem after all

At this point, if you haven't already done it, I would turn the switch to 4H and remove the servo motor and see if it is indeed in the 4H position. It should be very clearly marked on the transfer case where the servo motor attaches. On the '91-94 you can turn it by hand but I don't know about the later ones.

 

It's been a while since we owned our '96 but the best I can remember is that when equipped with the "control trac". When you turn the selector to 4H it will engage the transfer case and then lock wheels at the hub as they slip. I remember reading somewhere that you could run in 4H on dry pavement because the system didn't work like the old 4x4's. So potentially you could have all 4 wheels digging at any given time depending on how much the other three are slipping. I know that the '96 that we had, I tried to get it stuck before in the snow and couldn't. The only way to get stuck was to high center it with the weight off the wheels.