Hello all. I'm hoping I have come to the right place. I bought a new to me 2001 Expedition Eddie Bauer a few days ago. I knew it would have problems going into it but now I am getting in a little over my head. So I will start at the beginning and go from there.

I got the vehicle home from the purchase and pulled the engine codes. I got P0357, P0442, P0171, P0174, and P0307. I did my research on them and looked into what would be needed. I knew the 442 was most likely the gas gap, especially since the cap that it currently had didn't correctly click. I was right and a new gas cap fixed that problem. The P0171 and P0174 were also an easy fix. I figured it was most likely a dirty MAF sensor and I turned out to be right. While I was at the parts store buying the cleaner, I picked up an air filter too. I figured it was just safer to change the filter out and start my own routine. Turns out the codes were created because there was no filter and so that is why the MAF sensor was dirty. The P0357 and P0307 were both about cylinder #7 having a misfire issue. I lucked out here and only had to replace the boot for 5 bucks. So now all of my engine codes are cleared. Yay, go me!!!!

I have also replaced the engine oil, added some transmission fluid as it was low, replaced the fuel filter, and changed out the differential fluid. Next on my list is a transfer case fluid change.

So here are the major issues.

I can't select a 4x4 mode without blowing the fuse for my backlight on the instrument panel.

Putting the truck into any mode other than 4H results in 4x4 light being on but then not being able to drive forward.

Having truck in 4H mode results in being able to reverse but not more than at an idle speed, however the truck will drive forward just fine. The 4x4 light does not currently come on in this mode.

In A4WD it reverses better, but slips while trying to go forward. The truck just won't move forward.

I am assuming spinning the **** all the way to the left is A4WD and to the right is 4L. I don't actually know as I am missing the **** and have to use some pliers to turn it.

The wife noticed while I was cycling through the gears while filling the trans fluid that switching gears had a loud clunk sound, like a binding sound. Almost like when a brake pad sticks.

I also can't get the gear selector to go low enough to get the truck into first gear.

I don't know if any of this is related or if it is all related. I am just looking for anybody that could by chance point me in the right direction of what I need to look at.

Thanks

 

So here is a little update. Don't know if it would help diagnose it at all. I went and tested the voltages I was getting at my 4x4 selector switch. From what I had read, you should get about 1V for 4L, 2V for 4H, and 3V for A4WD. That is not at all what I am getting.

I believe this should be the reading for 4L



I believe this should be the reading for 4H



I believe this should be the reading for A4WD



Can anyone verify that my assumed readings are correct? Could anyone tell me why what I think is 4H is getting almost 12 and what I think is 4L is getting almost nothing at all?

If the selector isn't sending the right signal out to the transfer case on how to switch the gears, would that cause my issues of why I can reverse better in one 4x4 mode and not go forward and go forward great in another but not reverse?

 

Ok, I have tested the switch and the switch is fine. I can actually hear the transfer case working when I have the vehicle running. So I guess that is all good. I am assuming the 4x4 light doesn't come on when you are in A4WD. So I guess the next thing is figuring out why reverse doesn't work right and how to stop the #18 fuse for the illuminated dash to stop blowing when I change 4x4 modes.

 

The illumination lamps and the 4x4 lamps are all controlled by a microprocessor built into the instrument cluster. Since the fuse is blowing I would first remove all of the 4x4 related lamps in case one of them is internally shorted and causing the fuse to blow. If the fuse doesn't blow with the lamps removed then obviously one of the lamps is the problem.

For the rest of the problem you're having...to me it sounds like a mechanical issue with the transfer case. Something inside of it is binding or jamming which is restricting movement.