4x4 not engaging, help!

Hello everybody,

I just went out a few weeks ago and purchased a 2001 Ford Excursion Limited 7.3 PSD. As stupid as I was to not try the 4x4 system when I purchased it, I am just realizing that there is a problem with it now. I checked the owners manual for every possible solution and I figured I would try on here to see if anyone could help me. The hubcaps are engaged to "Auto" as of now, and when I try and turn the switch to 4x4 High, no light comes on indicating the switching over to the 4x4 High. I even went out and looked at if the front tires were spinning, and nothing. I checked the number 104 fuse "4x4 Electronic shift on the fly case" and the fuse was not bad. So I really do not know where to go from here. The 4x4 high and 4x4 low do not engage, nor show any lights indicating any switch. Any help??

Doughboy,
If you haven't already, try them in the locked position.

You may need replacements, due to the age and wear on your lockers. There are vacuum issues, seal failures, and the aforementioned wear and tear of age. This is the likely culprit. Here is a link to a situation that may be similar to the one you are facing.

http://www.thedieselstop.com/forums/f26/installed-new-warn-hubs-today-257233/index2.html

Not too expensive of an endeavor, and one you may be able to do yourself. I trust the folks at justdifferentials.com. I purchased new gears from them when I upgraded from a 3.73 gear ratio to a 4.10 gear ratio after lifting my Ex and putting on larger tires. This upgrade brought be back into the powerband.

Hope this helps...

I actually tried both. I tried the wheels in the Auto position first. When that didn't work, I tried them in the lock position.

The wheel hub locks actually have some resistance (more than I expected), but are not impossible to turn. I heard the main two issues that are most likely the case are either the vacuum hose is cracked, and or the transfer case motor is shot. I might be lead to beleive that it is the transfer case motor because when I turn the switch from 2x4 to 4x4 High, I do not hear any noises engaging anything.

OK...

Hope I helped. Good luck w/ your 4x4 ordeal. I have 6.0 PSD, and I picked her up for a reasonable price, because the Navistar 6.0 came with so many "isms". I corrected those isms with aftermarket products, and I couldn't be happier.

MWD

I don\\'t know your specific problem, but here are some things to consider. First, the truck has probably never been in 4 wheel drive ever. Because of this, everything is stiff. A lot of newer 4x4s are vacuum actuated. It might depend on a vacuum or solenoid to move a gear into place. If this is the case, you might need to try it a few times and have the truck warmed up. Even the switches on the dash might have oxidized and need massaging. Bottom line is I wouldn\\'t give up too easy and tear it apart. It just might need a few chances and a little time. Try it from time to time and drive around slowly and try it more than once. It might surprise you and work without doing anything except repetition...Dave