2004 Yukon XL 4x4 Transfer Case Issues

[Yukontommy]

First time poster here. My 2WD, N, 4H, and 4L selector switch doesn't stay in 2WD mode all the time. When I turn off the engine for a short period of time and then restart the motor, the drivetrain selector switch on the dash left of the sterring wheel goes into either the "N" (red light) or 4L (Amber light) position. And when it goes into the 4L position the truck has trouble getting going when trying to accelerate and it sounds like the trans or transfer case is making some clunky sounds like it's trying to make up it's mind. Then if I turn the engine off for 10-15 minutes, the selector switch will go back to either the 2WD or "N" position and the truck runs fine (even in the "N" position). But, it's can be dangerous in city traffic because when in the 4L position the truck hesitates when trying to accelerate from a light turning green or if I'm pulling out into traffic from a side street. I've replaced the pushbutton "Selector Switch" on the dash but that hasn't solved the problem. Any help and/or suggestions will be greatly appreciated. Thank you. Tom in SC

 

[Miami-Dade]

@Yukontommy Moved you here from 2021+section.

Welcome from Miami Beach&Queens NY!

 

[Fless]

Welcome to TYF!

Does the dash switch have an "AUTO" button at the top? If not, can you show us a pic of your switch?

Take a look at the RPO code sticker inside the glovebox lid and tell us your "N**" codes so we can tell what transfer case came with it. Or just post up a pic of the sticker.

The symptom you describe is likely caused by the commutator inside the encoder motor on the transfer case. See this thread for a bit more info:

4WD indicator lights shows Neutral

My 2004 z71 Tahoe is driving fine but I noticed that the 4WD indicator only has Neutral light on. I tried selecting the 2hi and it just flashed. When you start the vehicles, all the 4WD lights come on as usual.

www.tahoeyukonforum.com

Most people find it easier to replace the encoder motor as a whole part, but the commutator can also be changed, and the current encoder motor reinstalled on the transfer case.

 

[Yukontommy]

Welcome to TYF!

Does the dash switch have an "AUTO" button at the top? If not, can you show us a pic of your switch?

Take a look at the RPO code sticker inside the glovebox lid and tell us your "N**" codes so we can tell what transfer case came with it. Or just post up a pic of the sticker.

The symptom you describe is likely caused by the commutator inside the encoder motor on the transfer case. See this thread for a bit more info:

4WD indicator lights shows Neutral

My 2004 z71 Tahoe is driving fine but I noticed that the 4WD indicator only has Neutral light on. I tried selecting the 2hi and it just flashed. When you start the vehicles, all the 4WD lights come on as usual.

www.tahoeyukonforum.com

Most people find it easier to replace the encoder motor as a whole part, but the commutator can also be changed, and the current encoder motor reinstalled on the transfer case.

First of all, thank you for welcoming me to your Forum. Yes, the Selector switch does have the "Auto 4WD" button at the top of the switch and the "N" codes in the glovebox are: NP5, NP8, and NT9. Hope that helps and thanks for your assistance. Tom

 

[Fless]

NP8 is the 2-speed transfer case (NVG246) that takes Auto-Trak II fluid (it's blue). Verify that the fluid level is good. If you drain and fill the fluid it takes just less than 2 quarts. Always remove the "fill" plug before draining, in case it's stuck; you don't want to have a drained transfer case and not be able to re-fill.

This video shows how to change the encoder ring, but it also shows how to remove and replace the encoder motor as a whole (ignoring taking apart the encoder motor).

EDIT: IIRC the bolts for the encoder motor are long, so be prepared to turn that ratchet a while.

 

[rockola1971]

Yup encoder motor commutator ring(mounted on encoder motor) is dirty/worn and the 4wd system is lost and doesnt know what position the Tcase actually is in. If you were truly in Tcase Neutral the vehicle wouldnt move when in gear (transmission). If you were truly in 4wd Low while going down a highway the Tcase woulve exploded.