twr7cx

I have a 1998 Ford Explorer XT. Recently it has stopped engaging the front wheels when putting it into 4WD mode. Using the dial on the dash I can put the vehicle into High 4WD or Low 4WD, and it will engage the correct range ratio (i.e. it will engage low range), but it doesn't engage the front wheels to drive.
This first occured whilst traveling down a dirt/mud track with the result being that the vehicle was bogged in a mud pit, and despite being in Low 4WD, only the rear wheel was spinning, and towed out by another vehicle.
Any ideas as to what would cause this? I am wondering if this is perhaps an electronic issue?

360ci

The only electronic part here is the TCCM, or transfer case control module. If it was bad you wouldn't be able to select low range, it would flash at you and go back to your previous drive mode.

First off, check the transfer case fluid level. If it's fine, then I'd suspect a broken fork. The fork is what the TCCM slides back/forward to engage/disengage 4wd. Which would explain why 4LO still works. If your transfer case has only the one fork to push/pull the gear to lock it into 4wd, then it could be a bearing issue or one of the shafts has worn significantly enough to slip the front axle assembly altogether.

Now, the easiest way to check yourself is to find a friend with a hoist, or several GOOD jackstands and get all four wheels off the ground, and with rpm below 1000, and 4WD engaged, see if the front axle turns (just bend over, don't go under....). Who knows, the front differential might even be the problem....

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'06 Pontiac G6 GT 3.5L 220hp; 44,000m
'12 Chrysler 200 Limited 3.6L 283hp; 13,000m
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