F-150 FX4

ok did some loolin but couldnt find any post with my problem. got an 03' fx4 when i go put it in 4HI i hear a click and the light comes on but it will not ingage, not in park, revarse, neutral, drive, nothin, havent had the truck for to long just a few weeks. its pi$$in off just rained and cant even mud. and any one know a good mud tire for a low price and what size tire i can fit with a 2" leveling kit whit no trimming.

REGCABMAN

I am having the same problem with my 98 Navigator. Will yours engage 4 low? mine won't engage 4 high or awd but will engage 4 low not a big concern because I know if I get stuck I have 4 low. A mechanic told me I was a vacuum line.

F-150 FX4

nope not even 4LO will work.

n8sf150

I have had the same thing happeng to me for over a year now.I have been told it could be a number of things from a bad (GEM board) to vacum at the front diff.I have at least 6 post here and got good advise but still tring to figure it out.I was told a GEM was around $700 depeding on where you live.Let us know if you figure it out maybe it will work for me.

iowaredneck

Sounds like a vacuum leak, I had the same problem with my old 97 and that was teh problem. Can be difficult to find, but that sounds like your problem.

PAG-MX

Just my 2 cents, but have you checked all of your fuses & relays? As I understand, there are also some solenoids that have to be energized for the front hubs to lock in. I don't see them going bad at the same time, (if there are two, not sure, could just be one) but check to see if you are getting power to the solenoid(s). One other option to look at is the transfer case 4wd engagement motor. you might want to check that too. Of course, these are the items that cost a little more than vacuum hoses, but they are other ideas to look into. Good luck!

TheJMC

The first thing to do is eliminate the transfer case. Lift and support the front wheels off the ground. Key ON Engine Off Transmission in Park engage 4hi. Get under the truck and try to turn the front drive shaft. It should not turn. If it doesn't turn rotate one of the front wheels. The other wheel should rotate in the opposite direction. If it doesn't the front axle is not engaged.

F-150 FX4

ok TheJMC i did what you said, the drive shaft spun a bit but then locked up, didnt even spin 1/4 turn. tried to spin one wheel but when i did the passenger side it spun a bit but then got realy hard to spin, to where i had to pull prity hard to get it to move at all. so i stopped and went to the drvers side it was doing the same thing but, didnt stick as bad and it did spin all the way around, but when spining ether side the other did not move at all.

TheJMC

It is normal for the wheels to be difficult to turn but with the driveshaft locked in place by the transfer case and not moving the differential ring gear will not move. This will cause the opposite axle to turn in the opposite direction as the spider gears walk around the end gears in the differential. If the other wheel did not turn then the axle on the passenger side is not engaged. Do you have a vacuum pump with a gage? A multimeter or a test light?

luke5.4

This is what I did to diagnose my 4x4 problem - turn the key in ignition (don't start the truck), turn 4x4 on - the transfer case should engage and front drive shaft should be locked, next back to 2x4 and take out the fuse for transfer case(third from the top on left row in engine fuse box), turn the engine on and turn the **** into 4x4 - the vacuum should engage the front differential and front shaft should be locked.
In my case it is front diff, the arm moves just not all the way, thus 4x4 is not engaging, have to use wire to hold that arm - needed 4x4 for hunting.
The whole system is bad design - what's wrong with lever and cables?