Need 4x4 Help

[momto5]

Recently bought a 91XL. The 4 wheel drive won't engage. The 4x4 switch on dash won't light up. The fuse in power distribution box has been changed. Can anyone help me figure out what is wrong? Thanks, momto5

 

[Robb]

The transfer case shift motor is not engaging the t-case. If you remove the motor (looks like a power window motor) from the t-case, disassemble it, clean out the old grease, clean the contacts, regrease it, reassemble it, and reinstall it..........it will probably work like a champ.

 

[momto5]

Thanks, I'll give that a go. Most the things I'm trying are in the manual and I believe it tells how to remove the TC motor. I'll let you know if that doesn't work. momto5

 

[JDraper]

Check out Dead Link Removed if you need info on how to repair the xfer case shifter motor.

 

[momto5]

Does anybody know how accurate the test in the top of this article is? Because If it is accurate I know what is wrong with mt 4by4. I'm looking forward to your answers. Thanks, momto5

I was having some trouble with my 1991 Ford Explorer transfer case and talked with a service tech up hear in Alaska about it. He told me about a test you can perform to the processor board that is located in the rear left access panel next to the jack and rear windshield washer container. In has 2- wire harness pin connectors attached to it on the left side. If you remove the 2- wire harness pin connectors and turn on your ignition switch. Now you can push the white square button on the bottom edge of the processor board and it will turn on a red LED right next to the button. If the red light flashes this means you have a problem with your actuator motor assembly. If the red light stays bright this means you have a problem with the processor board. I found a problem with a the actuator motor assembly. I followed the instruction from your web page on Transfer case problems. I found it helpful but would like to add some info to it. I didn't need to remove the harmonic balancer nor drain the fluid. The 4 bolts that hold the actuator to the case were removed, the magnetic pickup sensor and I cut the one brown wire going into the case. I opened up the actuator and removed the armature. Cleaned it up with some 400 grit carborundom paper and washed it down with some CRC contact cleaner. I pull the brush holder springs out and put a little more tension on them because they seemed to only apply a little tension to the brushes that were worn to a length of about 1/4". I polished up the armature shaft where it comes in contact with the bronze oil impregnated bushing with the 400 grit carborundom paper. I install some graphite grease on the worm drive shaft and gear and bushing surfaces. I installed some RTV sealant on the cork gaskets before assembling. I removed the 3 -8/32 X1/2 " anti-theft screws on the gear cover and cleaned the face of the gear with the foil trace circuits on it and the 5 copper contact surfaces on the cover with CRC contact cleaner and 400 grit paper. I used some RTV sealant on the cork gasket before installing the cover. I also installed some RTV sealant on the 5 wires that go through the cover rubber grommets that don't do a good job at keeping out the fine dust that was found on the contact surfaces within. This I feel is the root of the problem! Now I cleaned up the transfer case and actuator surface where it meets the case and installed some ATV sealant on it and bolted it back together. I install a #14-16 pin connector male and female on the wire I cut and put some heat shrink tubing over it to seal it up. After 1 hour of tinkering I am back on the road. Wala- a simple push of the button and I was in 4 wheel drive again. The first snowfall in Alaska this year has now come and I am ready for it. With 4 studded tires I can drive on the glacier roads at 55MPH and feel safe.

 

[tcndeb]

Question: I looked at my board like you described. My board had two plugs connected to it. A 4 wire and another one with more than 4 wires. There was a two wire connector hangind loose back there, but I couldn't find anywhere to connect it. When I pushed the button, the red light stayed lit.

 

[momto5]

Is your 4 wheel drive working OK? I unplugged the connecter that on the module itself looks like it has two long prongs in it. None of the plugs I have back there only have 2 wires on it. That's why I want to know if this is a accurate test and if I did it right. Can anybody help please? momto5

 

[TheRookie]

I dont think you actualy need to unplug the connector. Also there is a way to get that brown wire off without cutting. I havent taken my motor off but a friend of mine has done this. Will ask him when I see him

 

[tcndeb]

Is your 4 wheel drive working OK? I unplugged the connecter that on the module itself looks like it has two long prongs in it. None of the plugs I have back there only have 2 wires on it. That's why I want to know if this is a accurate test and if I did it right. Can anybody help please? momto5

OK. I didn't unplug the module and see how many prongs were on each, I just counted wires. I haven't been able to jack the truck up and verify 4wd operation, but my son said it didn't work, (he gave me the truck), and the lights don't light up when I press the 4wd button on the dash.

 

[momto5]

I read somewhere else on this forum to do the test you unplug both plugs that have the clips on it. Then if the light burns steady it means bad module and if it flashes then bad or dirty shift motor. I havn't tried this test yet. Will try it out later. I'll let you know how it goes. momto5

 

[tcndeb]

Went back and reread your earlier post describing your fix. Stupid me. Big difference between a 2 wire connector and 2 - wire connectors. DOH. I tested mine with both connectors still in place, so I'll go home and try it correctly tonight. Thanks for detailing your work online. This board is great for newbies like me.

Added: Went home last night and pulled the connectors off the shift module and pushed the white button. Red light flashed, so it looks like I've got the shift motor problem. I'll fix it this weekend. Thanks again all.......