Problem with FX4 4-wheel drive system

[sunnyboy]

I've searched the internet for several days now, and everything I find is for older Rangers.

I have a 2008 Ranger FX4 with manual transmission. My 4-wheel drive problem is something I have not been able to find anywhere. Any help would be wonderful.

The system goes into 4Hi instantly. I can tell immediately when driving that it's in 4Hi as well. The problem is that it is really SLOW to come out of 4Hi and back to 2H. Sometimes it's immediate, but often I have to drive 1km or more before it suddenly returns to 2H.

In fact, if I'm stopped I can switch to 4Hi and again it's instant. I can hear the relay, and if I drive it's in 4Hi. If I stop and put it in 2Hi, it DOES NOT SWITCH. I can hear the relay, but again, I must start driving (in 4Hi) and then it will switch after anywhere from 1 block to 1-2 km.

My worst almost disaster was 4LO. I was testing the problem,and while stopped I switched from 2Hi to 4LO as per the owner's manual. It immediately went into 4LO. BUT... No way I could get it back to 2Hi. Nothing I tried - the owner's manual procedure, forward and back, a little driving - nothing.

Finally I tried putting it into 4Hi (it would not go immediately) but after some gentle forward and back (long driveway) it went into 4Hi. I could then put it in 2Hi and drive around the block and it went back into 2Hi.

Everything I've read says the usual problems are usually "no 4WD" at all (or no 4Lo or trouble getting out of 4Lo).

But this problem seems quite different - it goes into 4WD instantly, but is sluggish coming out of 4wd.

Listening carefully I can hear the solenoid in the dash behind the 2hi/4hi/4lo selector switch when I change the setting, and the quickness when it goes to 4wd suggests the transfer case selector motor is OK. I thought hubs but the 2008 has the live axle so I'm stumped at this point.

Thanks,

-S

 

[RonD]

Most common issue with the newer, 2002 and up, Rangers 4WD is the 4x4 shift module, it is located behind the Radio in the dash.

The fact you don't mention any 4WD lights flashing or not changing means the module is either going bad or is getting the correct feedback from the shift motor, shift motor has physical contacts that must touch to confirm motor has turned to a specific location.
If the motor is turning when you shift back to 2WD, then you would be in 2WD, it wouldn't change a few miles later, so my guess would be that the control module is not sending the 2WD command when you select it, it is delayed, why? not a clue

 

[sunnyboy]

Thanks Ron. That makes sense.

The lights do not flash, but do accurately show what's going on.

for example: switch selector from 2hi to 4hi. ranger immediately shifts to 4hi, light shows 4hi. (you can tell when the truck is driving 4hi vs 2hi really easily).

Next, switch selector from 4hi to 2hi while driving. Truck stays in 4hi for a while (from 1 block to 1km usually) and the light shows 4hi the whole time. Then it shifts back to 2hi and the light also shows 2hi immediately.

I can't think of a reason why the transfer case or the shift motor would be so sluggish - and only in one direction (back to 2hi), so it does sound like the electronic module.

Although, when stopped with the engine running, if you switch from 2hi to 4hi the light comes on immediately (and driving will confirm 4hi); plus you hear the solenoid click behind the radio.

BUT - if you then shift back to 2hi, you do hear clicking, but the light does not change, and you can't get back to 2hi unless you drive forward a bit.

So maybe something inside the transfer case is sticking? I will have to crawl underneath and have someone move the selector to see if the shift motor is indeed working. If so then it's inside the transfer case. (yuk).

 

[RonD]

That's the puzzle, if the shift motor doesn't change to 2hi when the module tells it to then the light would flash showing a problem, since the light doesn't flash............the module is confused about something.
Maybe the switch itself has a bad contact?
A little vibration makes it pass voltage to module

 

[adsm08]

Sounds like windup to me. Next time this happens drop it into R and roll backwards slowly to take the load off the system.

 

[sunnyboy]

Found out a week ago that the passenger hub is bad (bearings are shot). I installed a new hub today and although it fixed my ABS problem, it did not fix the slow return from 4hi to 2hi... it still happens.

Since it switches from 2hi to 4hi immediately (or into 4lo if I select) but is slow going back to 2hi, I guess the thing to check is the position sensors in the switching motor on the transfer case. Oh well, at least I have videos showing how to do that...