I've had this 98 Expedition 3 years now, and the one thing i can't seem to figure out is this random getting stuck in 4low thing.

Very very rare it gets stuck in 4high (4 times i think) and 20 or 25 times it wouldn't go into 4high or 4low at all since i've owned it, but for the past 9 months, mostly just getting stuck in 4low. I've had 3 shops look at it, new GEM, new 4x4 motor on transfer case, new relay behind dash, some other relay under hood, and the 4x4 switch on dash (every time i take it somewhere, they swear this is it) but sometime later, it'll do it again.

This doesn't happen all the time, i've gone weeks/months using 4x4 and it would work just fine, then out of know where, it gets stuck in 4low, sometimes turning the engine off than back on fixes it, and will go back to 2wd, but here of recent, this has not been working, and have had to pull the motor off and do it manually just to get home and turn it back to 4low, then to 2wd and it come out of 4low right there.

It's at complete random (though i feel it's getting worse now) like it just makes no since, makes no difference what temp it is, how long you've driven it or not, i can't find any pattern to it. I played with the brake switch and took the motor off the transfer case and turned the shaft manually, turns fine, everything seems to be fine, i changed the fluid (looked fine, no metal) i don't know where to turn from here, nobody at our local shops seems to know (or care besides throwing parts at it, i can do that)

Is there anything i can check/replace from here? at this point, i'm about to hot wire it to a window switch and feed the motor manually as it seems the 4x4 indicator lights on the dash work fine when i switch it manually by hand.

Edit! 5/8/25 to add, when it does get stuck in 4x4, there is no noise/clicking coming from the GEM or other relay inside, also, no amount of going forward or backwards makes any difference.

I'm really hoping i'm missing something here.

Thanks.

 

Next time it happens, pull fuse #17 out of the fuse box under the hood. This will remove power to the forward clutch in the transfer case and should free up the front portion of the AWD system.
On a second note, all 4 tires need to be the same size and approximate wear, otherwise the front and rear axles will fight each other and bind. In this event, back up about 20-feet, if the system shifts back to 2WD, then the tire sizes are the issue.

 

My money is on the t-case motor unless it was new, not a reman.

 

It came from Napa they said, but there was no difference before and after that part or any other part for that matter. I just came back from work with it, and the 4x4 worked fine, no issues today. So IDK