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- - 4x4 trouble (https://www.fordforum.com/forum/general-tech-11/4x4-trouble-6625/)

I bought a 1998 Expedition. We do love it. When I go to switch into AWD or 4WD High or low nothing happens. The lights come on but the tires do not engage and cannot here anything trying to happen either. Any thoughts before I ahve to go to the shop.

Could be the electric shift motor mounted 'externally' on the rear of the transfer case.. It drives a rotary cam which moves the mode fork and range fork inside the transfer case to select between the 2H/A4WD, 4WD HIGH, and LOW range positions.
Also, 'possibly' the shift motor sense plate ( integral part of the electric shift motor) that tells the GEM (generic electronic module) as to the position of the transfer case.

The Expedition/Navigators are also equipped with 2x4 and 4x4 vacuum solenoids attached to the upper right hand side of the engine compartment dash panel area.. They 'alternately' route vacuum to the vacuum motor which engages or disengages the center axle 'disconnect' collar in the front axle assembly, controlled by the 4x4 shift motor relays (relay module) throughGEM controlshiftingthetransfer case shift motor between the 2WD and the three 4WD modes..

If the previuos owner didn't use the 4x4 much, as far as I know, the shift motor was the most problematic..

Hi Hayapower, i have same kind of trouble , i have a 98 Expedition, but in my case the traction is permanentky in low 4x4, if
i move the swith to 2wd or awd nothings happens, i can't ear the relay, what you recomend me to do?, thanks

The only way I can get mine out of 4WD Low is to put the Transmission in Neutral. Cut off the engine. Turn the 4x4 selector to 4WD High, then crank the engine.

Quote:

ORIGINAL: TomDnSC

The only way I can get mine out of 4WD Low is to put the Transmission in Neutral. Cut off the engine. Turn the 4x4 selector to 4WD High, then crank the engine.

Wow. its a little bit time consuming erhh... You might want to let it get checkup. You might destroy your transmission by doing that.

just my 2 cents.

hi i used to work at a ford dealer and found a common problem is in the shift fork in the front diff,the fork only has plastic ears on it and they break off and wont engage the 4 wheel drive all the 4x4 lights will still work but front axle wont engage might want to check it out good luck