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Service 4WD

3347 Views 25 Replies 5 Participants Last post by  Whifflebat
My service 4wd light keeps coming on. Last night it stayed on for my whole thirty minute drive home. It never does that.

What the hell does this mean (besides the obvious)? I can't find my owners manual, and my back home GMC dealer says,

"Ah, don't worry about it too much. I's probably just a glitch." whatever :wank:

Well, the thing has been going on and off now since I got my truck towed. Something about it sticking too far out into the road. (stupid tiny compact european car parking spots) :flame: So I don't know if that has anything to do with it. But it DID start happening right after I paid to get it off their lot.

Any answers from anybody would be greatly appreciated. Also, if there is a way to turn it off after I get it fixed would be nice too. (Kinda like when you change the oil.)
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I would check the actuator on the front diff, its a common failure point. When the light is on will it not shift in 4x4?
:confused: What does the actuator look like, what would I be looking for when I get underneath my truck? :think:
its about the size of a coke can on the passenger side of the diff.
Ok, so I find the coke sized actuator on the passenger side of the front diff...what do I look for? A hole? A squirrel? Sparks shooting out? A loose wire? :shrug: I just don't know...
Get the code pulled first before doing anything, that will steer you in the right direction, otherwise you are just guessing.
I forgot, it is an automatic or manual t-case?
c2ingram said:
Ok, so I find the coke sized actuator on the passenger side of the front diff...what do I look for? A hole? A squirrel? Sparks shooting out? A loose wire? :shrug: I just don't know...
Well check to see if its got loose wires going into it. A hole would be a bad thing and please let me know if you find a squirrel because that would be just plain cool. If its not something obvious then get the codes pulled. Also sparks shooting out is perfectly normal dont worry about it :crazy:
jebx said:
I forgot, it is an automatic or manual t-case?

automatic, I need to take it to my hobby shop to have the codes pulled again. The guys who worked there didn't divulge that information last time. :flame:
Dark Eternal said:
Well check to see if its got loose wires going into it. A hole would be a bad thing and please let me know if you find a squirrel because that would be just plain cool. If its not something obvious then get the codes pulled. Also sparks shooting out is perfectly normal dont worry about it :crazy:
:LOL:

Yeah sure, I'll check to see if the wires are loose or something. But it might not be a squirrel. I haven't seen too many of them here. Maybe a chipmunk tho :think:
jebx said:
Get the code pulled first before doing anything, that will steer you in the right direction, otherwise you are just guessing.

I'm finding it hard to get the codes pulled from it because they come on whenever they want to. And as far as I know it isn't queuing them up in the computer. I had my SES light come on, and the Service 4WD at the same time, but they were only able to pull the SES code. :shrug:

Maybe my truck is just screwed up :bawl:
The codes should stay in the computer till they clear them....
:word:

The switches are common to go bad, as is the transfer case actuator motor. If it's the t-case actuator they run $300-$500USD I have seen. The code should point you in the right direction.

Is it an ODB2 vehicle?
Whifflebat said:
The codes should stay in the computer till they clear them....

That's what has me wondering. The light will come on some days, stay for about 5-10 mins, then dissapear for a week or two. Then they'll pop up again. The longest they've been on though was a few days ago and that was for 20 mins. :think:

I guess I'll just have to take it over there again to have it diagnosed. I have to pull a code for which o2 sensor is bad also. :shrug:
Even if the light isn't on, the code is still in the computer, they should be able to pull it off no problem, if they know what they're doing.
I'm calling the auto shop in a few hours. Hopefully I'll be able to get my truck in today or soon...like tomorrow soon. It sucks having all these damn lights come on ruining my day! :bawl:
Just think of it like christmas, lots of lights!
jebx said:
Just think of it like christmas, lots of lights!


:LOL:




I really laughed out loud when I read that!
Been a while since I did anything with the 4wd, but...I put my truck into 4high and now it won't come out. Also, it feels like my tires are rubbing. But they can't be because I don't have big tires. I can't turn my full radius and when I do turn the truck doesn't want to "center." Almost like the steering shaft is stuck or something. Any help?
if its stuck in 4wd, then thats why. there is no differential in the transfer case, so any speed difference between the front and rear wheels (like when you're turning), on solid pavement, will cause it to bind and thats probably what you're feeling.
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