Hi. I have a '93 Explorer XLT, Auto with 120,000. Bought it last May and the 4-wheel drive quickly stopped working after I bought it. No lights came on. Just the clicking from the l/r wheel well. So After a year of no 4x4 at all, the light next to the button came on suddenly and the truck feels like it is trying to shift into 4x4. No actual 4x4 light on the dash, just the round light next to the button. If I push the button to shut it off, sometimes it goes off. Most times it just stays on. If I get the light to go off, it comes back on by itself and again feels like it wants to go into 4x4. I hear clicking and feel the floor vibrating with a kinda grinding sound. Does not sound good. Is it safe to drive and try to see what it wants to do? I'm hopping it goes into 4x4 and then works like it should. But I think it may be electrical and the 4x4 needs a lot of work. Can I disconnect the 4x4 somehow, maybe pull a fuse and at least get to drive the truck? Thanks.

 

This behavior is indicative of a transfer case shift motor needing service. 3 bolts to take it out, make sure you check the position of the shifter in the TC housing, it can be moved by hand to put it into 2wd position
the shift motor can be stripped down and cleaned, or buy a new one for 500.00+, good luck

 

I know a guy with a '94 Ranger, I think, who was able to just clean the contacts on the transfer case motor. That's third hand info, but from what I understand, it worked for him.

 

Thanks for the help. Is there a connection I can unplug or a fuse to pull just to drive it for a few days? I assume there is a fuse that will stop the power to the transfer case and I can try to get under there and take it apart ina a few days. Thanks.

 

hi Max,
you could try, (disconnect or cut) the single brown wire that feeds the clutch pack, you will have to do this eventualy to service the unit, this will disable 4x4high, if it is trying to engage low range best to pull the shifter motor and manualy put it in 2hi untill you have time to work on it.

 

Aquanut - what are you talking about? "(disconnect or cut) the single brown wire that feeds the clutch pack"

Do not do this! There is no need to cut any wires servicing the t-case shift motor assembly. The connector is easily disassmbled. Get a paper clip and bend about a .03" 90 on one end and you can pull out the little plastic retainer on the center pin (brown wire), gently pry back the plastic retaining tabs and the pin is easily push out the back end of the connector.

See this web site for all the directions you will need in servicing the motor assembly. Total job is about 2 hours. Be careful of the gaskets when disassmbling. Total cost $0.
http://draco.acs.uci.edu/explorer/

And before you do anything else, hit the relay rest button to tyr and gett the motor squarely back to 2WH. Button is on the bottom of the relay pack. Relay pack is in the left, rear quarter panel. Accesebly by removing the jack cover. This is why you hear clicking from that area.

 

Sweet! Thanks for the link!

 

Internet, information - priceless! Here's a thread I wrote a while back after I fixed my 4WD engagement. Should give you a little more insight.

As suspected, my assembly was very clean. Minimal soot around the brushes and copper pads they ride on. The sensor plate with the printed circuit board traces looked fine but I cleaned all that off anyway.

I also had no issues removing the brown wire from the connector that derives from within the transfer case. I used a small pick tool that I had to remove the, red on my truck, inner plastic retaining peice inside the connector. One could fabricate such a tool with a thin paper clip bent 90 degrees at the end about .03"-.04" long. Then, a small screw driver to hold the plastic clip away from the metal pin and then push the pin through the back. One does need to be a little cautious here though because the metal pin is has 3 slits down the lentgh to give it some spring inside the female side when conneted. This makes the pin not as strong as it looks - it is not solid metal.

So then, if mine was so clean, why didn't it work? The worm gear has a screw inserted such that its head acts as a stop on the inside of the housing once installed. I'm not certain on this part, but I think the PCM uses time to move the motor to the 2 extreme positions - 2wd and 4wd low. Thus the PCM says go 4wd low, run motor for 30 secs - or some amount of time that is long enough plus some more time to be safe that it gets there - and then the worm gear hits the stop and the motor just stalls for the remained of the "time". When you hit the switch to go 2wd, PCM does same thing but in reverse. For 4wd high, the middle position, the PCM would then just use the sensor position to stop the motor travel. The traces on the printed circuit board seem to support this theory.

Now the stop screw head has a plastic bushing around it. Since mine was busted up it was difficult to measure. I replaced it with a piece of polyurethane 1/4" fuel line that gave it a nominal 3/8" final outer diameter. Looked to be close to the original design.

Although dirty contacts, spent brushes, bad windings...could all stop the 4wd from properly engaging, I think the key problem with this entire 4WD lack of engagement is that when this plastic bushing goes away, the motor is driven a little further than it is supposed to. Then the sensor tabs come off the traces on the printed circuit board. Next time you hit 4wd, the PCM does nothing because it has no reference point - doesn't know where the motor is. The program is probably written that if no reference, end - do nothing.

Again, I'm not the Ford engineer that designed this system. But I think what I've described makes sense. Particularly since, the only thing I really changed was adding this stop bushing back. I reassembled everything back to the exact polar alignment where I took it apart - since the gasket ripped on the sensor assembly leaving a peice on each side, I was forced to realign it exactly in the same orientation.