Intermittent 4wd issue

rockstar

Original poster
Member
Dec 14, 2011
14
Hopefully someone on here has seen this issue before and can enlighten me. The other day I parked my truck off-road to do some hiking and climbing. It was in 2wd. When I got back and tried to drive out I found I was stuck. Thinking this wasn't a problem since it's 4wd I shifted it from 2wd to 4hi. I heard the distinct whirring sound and the light under the 4hi flashed with the light under the 2wd staying solid. After a few seconds the service 4wd light came on. I shifted it back to 2wd and after a short whirring sound the flashing light under the 4hi stopped flashing and went out. The service 4wd light was still on. I turned the truck off then back on and the service 4wd light stayed off. I shifted to neutral and tried to go into 4lo with the exact same symptom. I tried this several times with no luck getting it in any 4wd selection. Luckily I was able to get it unstuck and out in 2wd. I got back to my camper and played with it a bit. It did eventually shift into 4wd and now seems to work but every once in a while is giving me the same symptom (I've been testing it for the last couple days). Any ideas of what the problem may be? I don't want to end up with an expensive repair in the end.
 

ConeKilrAutoX

Member
Dec 8, 2011
1,179
i have had a similar issue happen to me a while back and after 2 months of intermittent failures of the 4wd functions I started by removing the fuse for the ATC which is front fuse #8. I found I had a short in the actual fuse box connection that did the EXACT same thing to fuse #9 for my front washer squirters. I simply fiddled with the fuses to make sure they had strong contact and it has been good since. it was frustrating and I thought it would be a much bigger problem but so far so good that was 6 months ago. hope this helps or it is something little...
 

The_Roadie

Lifetime VIP Donor
Member
Nov 19, 2011
9,957
Portland, OR
There should actually be TWO distinct noises. One high pitched and longer-lasting that ONLY happens on a 2HI->A4WD transition (and vice versa) and the other one lower pitched and shorter duration that happens in EVERY mode transition. You can do this in your driveway with the ignition on but the engine off. Report back what you hear for noises.
 

rockstar

Original poster
Member
Dec 14, 2011
14
I can't get it to fail. It only happened the one time and intermittently for a couple days. Now it's shifting in and out fine. But if I remember the sounds where the same as they are now when it failed to go into 4wd but like I say it wouldn't go in and the service 4wd light came on. I could clear the light by simply turning the truck off then back on. Could it be old fluid? Or maybe because I hadn't had it in 4wd for about 3 months? I want to think everything is ok but am worried if there is a problem I could just make it worse by not dealing with it now. Plus I do lot's of back country camping and would hate to get stuck in the woods with a 4wd that won't go into 4wd.:undecided:
 

Voymom

Member
Feb 3, 2012
2,523
rockstar said:
I can't get it to fail. It only happened the one time and intermittently for a couple days. Now it's shifting in and out fine. But if I remember the sounds where the same as they are now when it failed to go into 4wd but like I say it wouldn't go in and the service 4wd light came on. I could clear the light by simply turning the truck off then back on. Could it be old fluid? Or maybe because I hadn't had it in 4wd for about 3 months? I want to think everything is ok but am worried if there is a problem I could just make it worse by not dealing with it now. Plus I do lot's of back country camping and would hate to get stuck in the woods with a 4wd that won't go into 4wd.:undecided:

I had this very same issue during the winter. Hubby and I discovered a loose wire. Once we got it tightened like it should have been, it worked fine. I haven't had a chance to test it out yet as it's been a few months and I don't get in situations where I need 4wd, although once we get some rain, I'm going to go exploring :smile:

Roadie is right(as always) lol get to know the sounds it makes, it makes life a whole lot easier!
 

rockstar

Original poster
Member
Dec 14, 2011
14
It had a 103,000 miles when I bought it and now has 113,000. I've only had it 6 months. Right after I bought it I put Mark's lift on it and took it to a mechanic friend to have it aligned. I also had him flush the radiator and do some other maintenance but can't remember if that included the running gear fluids. I'll have to call him in the morning and see if he can remember. Is there a simple way to check the grease on the splined disconnect without pulling the whole thing apart? I live in southern Arizona so don't need to use the 4wd very often because of how dry it is. Once the monsoons hit I'm hoping to get it buried in the mud and want the 4wd to be in top shape.
 

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