2004 Tahoe Possible 4WD Issue

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Fless

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Are the instructions that simple?
As soon as I understand this, I'll have my mech install a switch in the ground wire circuit.

Also, if I implement this, and then press 4Hi, what happens?

All you'd need to do is kill the power circuit by switching the B+ or the ground. I'm pretty sure that my actuator ground comes from the body mount under the driver's door hinge, up the firewall, then down to the actuator.

Diagram for your connector at the diff actuator:

Capture.JPG

So if you did that while in 4hi, you'd actually be in 2hi (RWD).

Not sure what codes or messages you'd get, though. Body grounds from upfitter guide attached.
 

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Marky Dissod

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OK, I think my mech can figure this out. Don't want to lose 4Hi.
(Pressing 4Hi to be in 2Hi, seems redundant, no?)

Merely want to gain the OPTION to lose 4Lo / HAVE 2Lo.
 

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OK, I think my mech can figure this out. Don't want to lose 4Hi.
(Pressing 4Hi to be in 2Hi, seems redundant, no?)

Merely want to gain the OPTION to lose 4Lo / HAVE 2Lo.

Yes, that would be redundant.

Just don't actuate the cutoff switch, then, when you want true 4wd, Lo or Hi. Only open the circuit when you don't want that front diff engaged.
 

Marky Dissod

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Fancy, but the no cost method would be to unplug the front diff actuator when you're ready to go 2Lo.
Yes, you'll get a code, but it'll go away when you plug it back in.
You could also put a switch in the ground wire circuit for the front diff actuator.
All you'd need to do is kill the power circuit by switching the B+ or the ground.
I'm pretty sure that my actuator ground comes from the body mount under the driver's door hinge, up the firewall, then down to the actuator.

Diagram for your connector at the diff actuator:
View attachment 453997
So if you did that while in 4Hi, you'd actually be in 2Hi (RWD).
Not sure what codes or messages you'd get, though. Body grounds from upfitter guide attached.
Yes, that would be redundant.
Just don't actuate the cutoff switch, then, when you want true 4wd, Lo or Hi. Only open the circuit when you don't want that front diff engaged.
 

rockola1971

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OK, so apparently I rambled too much, trying to explain exactly what happened, and confused everybody. Or just didn't explain it right. Either way, sorry.
My mom lives about a mile back in the hills (mountains) of WV. Big mountains. You actually used to need 4WD to get to her house. It used to look like a 4-wheeling trail. People that don't already know someone lives up there, don't believe someone lives up there when you tell them. The majority of the road was fixed by the electric company a couple years ago because they put these big power tower things all the way up on top of some of the mountains, to cut down on power outages. Naturally, them being who they are, they fixed this road so extraordinarily, you no longer need 4WD to go up it. It's still as steep as it ever was, but it's wide, smooth, packed in super tight, and graveled. Now, it seems people are coming from miles around just to play in my mom's driveway, get high (I literally had to run a couple guys in their 70's off a couple weeks ago that were up there "looking for somewhere we can get high." The one driving was actually wearing the little oxygen tube under his nose!). People pull in her yard all hours of the night, running stuff over in her yard. This is why I was up there putting signs up that day.
Anyhow, the driveway is a steep incline for close to a mile, then it levels out for about a 10th of a mile, then it drops downhill (steep) for about another 10th of a mile, and you're at mom's. Vice versa when you're coming back out from mom's. The power company fixed the main uphill part, but not the level part or the downhill part coming into mom's yard. Those parts still look like old 4-wheeling trail, seriously uneven, a big rut, clay mud, big rocks, an actual big tree root in one spot, etc.
I live on the main hollow (pronounced "holler"). If you go on up the hollow past my house, about a 10th of a mile, you'll find the bottom of my mom's driveway.
The ABS box has been leaking for a hot minute, so I try to stay off the brakes as much as possible, to keep from spewing so much fluid. Ever since it started leaking, anytime I'm going downhill (off-road), I try to keep it in 4LO, 1st gear. It almost drives itself, I rarely have to touch the brakes.
So when I went up the hill the other day, everything was normal when I left my house. I went up mom's hill like always. When I was about to start down the downhill part, I stopped to put it in 4LO, 1st gear, and all the lights on the selector were off. The DIC said "Service 4WD." I pushed 2 buttons to see if it would work anyways, and when nothing happened, I went on to mom's in 2WD, in neutral. The reason I chose neutral instead of drive was because when it was in drive, it seemed to be pulling itself forward, making me have to press the brakes even harder. I turned around and left. It took me 4 tries to get back up the downhill part because this is part of the road that still looks like 4-wheeling trail. Once I got back up on the level part of the road, I turned the truck off. It ended up sitting there between 2-3 hours total. When I started it back up, 2WD was lit up on the selector switch like usual, the DIC said nothing about 4WD. But where I had spent the past 2-3 hours thinking and stressing about it, I truly thought I must've lost all the TC fluid. The only thought going through my mind was to try to get the truck back off the hill and back to the house ASAP. I just knew the case was going to totally fail and I was going to get my truck stuck out there on that hill. That's why I didn't even think to try any of the 4WD buttons at that point. So I came all the way back out of there in 2WD, in neutral (again, because in drive, it seems to pull itself and makes me ride the brakes harder than in neutral). When I got all the way off the hill though, I put it back in drive and when I went to give it gas, all it did was rev the motor. Like it was in neutral. I looked at the dash, it was in drive. The 4WD selector was in 2WD. Nothing was in neutral. (My 4WD selector doesn't have a button for neutral).
I honestly believed it was done for. That's why I couldn't believe I was able to move it the next day. Neither me or my ol' man knows what to think of it. No one I've talked to about it seems to know what to think of it. I do know it's got me scared to even take it 3 minutes down the road because I'm scared it's going to leave me stranded somewhere. I don't want an unnecessary tow bill on top of everything else. I don't know whether we should try to fix this one or just start over with another vehicle. I don't even know what to try to fix on this one. I've spent hours reading online. I just don't know.
Your NP246E Tcase does indeed have a "neutral button". If you inadvertently push 2hi and 4hi buttons at the same time for 10 seconds your TCASE will go into neutral.
 

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