Another 4x4 issue, but not like others

[JohnVH]

'98 F150 5.4L, electronic 4x4 dial shift... It wont do anything, its in 4low, wont switch out, wont switch into anything, any idea's? Driving from one town to another in low is not fun.

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[FX41]

First, check relays and fuses. Get back to us after that.

[JohnVH]

ok, Ill make sure, I had this problem last year, but then it went away and worked great up until yesterday... At first it wouldnt go into 4hi or 4lo, it was staying in 2wheel, then shortly after it went into 4lo, and now its stuck there..

Thanks.

[JohnVH]

Ok well, everything is in order, cant find anything wrong.

does that electric motor on the transfer case ever fail? any way to manually put the truck into hi range so Im not driving around town in low?

I appreciate any other help.

[jbrew]

Most of the time there's a problem with the vac lines coming from the solenoids on firewall and going to the Actuator on the front axle. The lines for axle are color coded. The 98 lines are pink and light blue. They supply vacuum. Could also be a solenoid, but lines are damaged between the firewall and battery .

The harness to the actuator also includes and open tube. - That's the breather. Check those lines and make sure the breather tube is clear.

When engaging/disengaging 4 lo you have to be stationary and go from neutral to park and sometimes reverse/roll/stop/ neutral/ park before it will work.

Have you been working near the battery ? I broke both lines once just moving them around. They become brittle over time and fracture very easily.

I forgot to say - The number one reason why this doesn't work is because of the plunger rod on the axle freezing up. You have to grab that with pliers after soaking w/WD40 and work it back and forth to free it up. Don't pull the the Actuator off, you'll probably break it if you attempt (they cost about $150). Just work that pin/plunger on the axle, next to the actuator.

[Bindernut]

If it's not switching ranges, then there's a problem somewhere in the transfer case motor setup. Could be a bad relay block or just corroded connectors on the shift motor harness too. The motor could be bad too. If it's intermittent, I'd suspect a bad relay block or connection first.
You can test the motor itself by unbolting it from the transfer case and watching to see if it rotates clockwise/counterclockwise as you try to select a different range. If it is turning, then unfortunately it probably means that the problem is inside the transfer case.
You can also try to turn the shifting cam shaft that the motor attaches to by hand when the motor is removed...there is nothing to hold it in place though so this is just a shop test procedure. Don't take off down the road with no motor attached to the transfer case...it can jump into different ranges on ya. The case has marking on it that will index with the shaft to let you know what range the transfer case is in. If the transfer case can be shifted manually, then you'll need to look into the motor power setup some more.

I'd still check out the front axle vacuum actuator lines, and solenoids as jbrew suggested too but the GEM module is dumb. (There's no feedback from the actuator to tell the GEM if it's engaged or disengaged or if you've got broken vacuum lines...it'll say it's shifting but just won't operate the front axle disconnect)

[jbrew]

Originally Posted by Bindernut

If it's not switching ranges, then there's a problem somewhere in the transfer case motor setup. Could be a bad relay block or just corroded connectors on the shift motor harness too. The motor could be bad too. If it's intermittent, I'd suspect a bad relay block or connection first.
You can test the motor itself by unbolting it from the transfer case and watching to see if it rotates clockwise/counterclockwise as you try to select a different range. If it is turning, then unfortunately it probably means that the problem is inside the transfer case.
You can also try to turn the shifting cam shaft that the motor attaches to by hand when the motor is removed...there is nothing to hold it in place though so this is just a shop test procedure. Don't take off down the road with no motor attached to the transfer case...it can jump into different ranges on ya. The case has marking on it that will index with the shaft to let you know what range the transfer case is in. If the transfer case can be shifted manually, then you'll need to look into the motor power setup some more.

I'd still check out the front axle vacuum actuator lines, and solenoids as jbrew suggested too but the GEM module is dumb. (There's no feedback from the actuator to tell the GEM if it's engaged or disengaged or if you've got broken vacuum lines...it'll say it's shifting but just won't operate the front axle disconnect)

Right. The bad thing about those lines when they become brittle, - they can fracture/split making the leak hard to find. This forefits your presure needed to actuate the axle. (But yea, he managed 4LO ? Huh, - it might be something more than what I'm thinking) A simple cheap vacuum tester works great for testing and you won't have to tear the damn thing part. The Zone has cheap testers for around $20. They have colored smoke tester now for the vacuum systems , they are cheap as well.


The motor/solenoids could definitely be the problem. Starting with the most common probs and cheap ones to repair.

257,000 miles on the motor I use for the system, haven't had a prob with it yet. Still, you never know.

The front axle plunger to fork should be a maintenance item. = Most common problem in these systems.

[JohnVH]

Checked vacuum lines, breathers, this all goes to the front axle and has nothing to do with the transfer case issue not switching from low to high range....

I got tired of getting wet in the snow falling off the truck today, Ill try it again next time its dry I guess..

Im soooooo frustrated with this thing today. Can I manuall switch it out of low range? I see how to manually switch it out of 4x4 with the front axle vacuum system.

Thanks

[jbrew]

Originally Posted by JohnVH

Checked vacuum lines, breathers, this all goes to the front axle and has nothing to do with the transfer case issue not switching from low to high range....

I got tired of getting wet in the snow falling off the truck today, Ill try it again next time its dry I guess..

Im soooooo frustrated with this thing today. Can I manuall switch it out of low range? I see how to manually switch it out of 4x4 with the front axle vacuum system.

Thanks

So, I take it the plunger and fork work with out a problem / Guess so ehh - You didn't say . It has to move as explained above/ engine off/stationary.

TJK talked toFORD service - That's what the problem is most of the time. 5 minute fix.

Good Luck.

[JohnVH]

the plunger/fork work easily.

Who is TJK?

I took the motor off the T case, it doesnt move when the switch is moved, all the fuses are fine, what next?

[JohnVH]

Oh, by the way, yesterday I put a new battery terminal on the negative, now the truck always wants to put the front axle out of 4wheel drive, and the lights in the dash dont light up saying what mode its in.. (4lo, 4hi, etc)..

Also, the radio has a little square on the screen on the right side now, didnt before. odd!

Any idea's?

[blueovelboy]

so it all started when you replaced the battery? sounds like you need to reset the computer put the key in and turn to the on pission but don't start it then remove the positive lead of the battery for 30 seconds then touch it to the terminal and pull it off and then put it all back together and turn key off then try starting it see if this fixes your problem

[JohnVH]

Hi Blue, no, it all started on its own, in the morning the 4x4 worked fine going from 2wd to 4wd, in the afternoon the truck wont switch into anything.


But I will try that reset thing anyway, cant hurt. The battery stuff happened when I replaced a terminal, after having the transfercase issue. And it made it worse.

Thanks
John

[rogue1]

Mine was doing the same thing, and it was the cheesy center axle disconnect. The pins on the aluminum shift fork were gone. It would engage at times if you switched it on and off. You could hear it trying, but it wouldn't engage, and when it did, you couldn't get it back in 2X. The specialists that worked on mine had done dozens of these. The dealer was out of them because of high demand. Of course you should check the simple things first.

[JohnVH]

thanks, I dont hear mine try to switch anything, and the electronic motor doesnt try to move either.