Hey All - I have what I think may be a similar problem.

First some history. I have a 2005 Silverado Z71 truck with the electronic 4 wheel drive selector. It has about 97K miles on it and I have had the service 4WD pop on and off over the last few months.

I was driving up north - about 300 miles into my trip my truck popped into Neutral (the selector was STILL in D). I was cruising in Cruise Control and the revs went up. I immediately slowed down and moved the shift selector back to Neutral and back to D...everything was fine as the gear re-engaged, this happened twice on the trip. The next morning the truck started fine and I selected reverse and the truck would NOT move...just revved. Long story short I changed my 4x4 selector switch to 'auto' 4x4 and everything is fine. when I change back to 2H the truck will slip back into Neutral.

I took it to a mechanic (which I HATED doing - I normally work on my own vehicles)...the guy told me I needed a NEW Transfer case. That seems odd...since there are NO weird noises while driving and I made the trip back home (400+ miles) with NO issues using the Auto selection with my 4x4 selector. Would this possibly mean that my Transfer Case Encoder Motor needs to be replaced?

Any thoughts help are greatly appreciated!!!

Thanks

 

I have a 2007 tahoe with similar issues. Service four wheel drive appeared and gave me a code c0327. Supposely this means encoder motor.Encoder motor is about 310.00. Encoder sensor was 70.00 . Money is tight so i went with the sensor. Put it all back together,no codes ,no messages but still does not go into 4h,4l,or auto.With the ignition on you can here the encoder motor engaging by turning the selector ****.So i went to the axle actuator verified it works or it is at least getting signal.Pulled the trec fuse to try and reset the tccm ,no luck. Even unhooked the battery overnight still nothing.Lights on selector **** do light up. Any help would be greatly appreciated

 

Well - I won't be helping on your issue but I will expand on what I ended up doing. I replaced my sensor. When I took everything apart, I could clearly see that my sensor was worn down to nothing. I replaced it about 20k miles ago and everything has been perfect since. I have all my offroad modes and no issues what so ever.

The hardest part about it all was putting the motor back into the transfer case. that took me about 45 mins of attempted fittings.

As far as what you got going on...if you had it scanned and the code told you the motor...it very well could be that. I never had mine scanned...I just searched the forums and used my own logic to pin it down. I was also lucky enough that the truck ran fin in 'auto'.

 

maybe there were certain steps in this procedure i'm missing.I bought a new encoder motor assembly and still no difference. It was a waste of hard earned money. However with the encoder motor assembly connected to the harness, i swapped the 30 amp trec fuse with another 30amp fuse and the selector **** started to take all positions.I did not have the assembly bolted to the transfer case. It was like the tccm woke up but went back into sleep mode.By the way neither of the fuses were blown.Anyway back to square one the truck is drivable in 2hi with no codes present and drives fine ,but sure would like to know if i needed 4wd it would be there.I'm wondering if another sensor on the transfer case is bad.

 

Had problems with my 2001 4x4 similiar to yours. First I cleaned all grounds especially the one on frame by drivers door. Helped a little but problems came back, changed encoder motor 3 times thanks to dorman china crap, then found a USA rebuilt and back in action for a few days. Ended up being the module located left of instrument panel on my truck. Found a good used one and no problems with code or computer adapting. I'd still try all the ground associated with the 4x4 system first.

 

offroad z - when you put everything back together...did you make sure that the position was in the same place as when you removed the encoder motor?? I marked everything and it was a biach to get it all lined up again. That is why it took my about 45 mins to put it all back together again.

It sounds to me like your motor is 'working' that your switch is working and that if you are hearing the noises of it switching...maybe it's just not switching to the correct spot?? As I stated...since replacing my sensor everything has been fine (I've put almost 20k miles since replacing it).

Good luck!

 

Have the dealership check the wires. Just had a corroded wire replaced along with some connectors. I just went through the same thing with my '05 Silverado.