2003 Tahoe Transfer Case starts in N/4LO

[jjwg3]

My 2003 Tahoe with the NP8 Transfer Case seems to be having trouble. It first had pump rub and sprung a leak so I got that changed out. Now whenever the truck is started the 4 button selector switch reverts to either Neutral or 4 LO. I can use the buttons to manipulate it back to 2WD and everything works and drives fine. Next time I start the truck, back to N or 4LO. It seems so odd because it never makes any noise going into 4LO, but you can sure hear the commotion coming back out of it and getting to 2WD.

Would this be the actuator motor? It doesn't seem like its the 4 button switch as they all light up on start up and they all seem to work to do what they are intended to. But shut the truck off and it's back to the beginning.

Thanks for any input, John

[777stickman]

I would be inclined to suspect the T-Case Control Module as the motor seems to do as commanded.

[jjwg3]

That makes sense. I'm thinking that's under the dash. I'll start looking into that. Looks like a couple hundred dollar part, not so bad if that would take care of it.

[aleekat]

In my older Chevy Blazer it was under the passenger knee/foot panel. I'd be checking for a used one first.

[jjwg3]

Used does sound like a cash saver...

[jjwg3]

Update. I was able to change the control module and while it did seem to help, it still was random where the gearcase would be upon starting the truck. and then one time the switch stopped giving commands and had no lights. Shut the truck off, restarted and was able to tell it to come out of 4 LO and back to driving. So I figured it was the switch itself and changed it, cheap enough.

Unfortunately it still does random stuff about 25% of the time when I start the truck. Now it likes to start in the N (red light) of the switch and sometimes up in AUTO 4WD. But it still occasionally starts in 4LO.

Im baffled. It still takes commands and I can get it back to 2WD to drive the vehicle, but this is getting old. Any thoughts appreciated.

Lastly, could I consider pulling a fuse while it is in 2WD and just leave it disabbled unless I actually wanted to use 4WD? It's very rare for me to use it.

Thanks for anything, John

[j cAT]

because this is intermittent electrical issue check the wiring from the under hood fuse box to the transfer case .. the loom breaks down then those very fragile wires do cause the problem..

[jjwg3]

Thanks for the reply. This is still happening and my local garage can't figure it out either. The wiring loom makes sense, thanks for pointing that out.

Another question, if I have it in 2WD, could I pop a fuse out to ensure it stays in 2WD? I rarely need the 4WD and I have had times when it started in 4LO and wouldn't take commands. That's a major problem!

Thinking I maybe just pull the fuse and stay in 2WD??

John

[777stickman]

I would think that YES you could pull a fuse to disable it. Look for a fuse labeled "t-case". Know that doing this will prompt an amber message on the instrument panel.