HELP PLEASE: 2006 DURAMAX/ALLISON 4X4 "SERVICE 4X4"

[mountainhorse]

I know that there are some pretty sharp mechanics and owners on here ...

I have a 2006 Chevy Silverado 2500HD 4x4 that will not go into 4x4.

When I push the button on the dash for the 4x4-Hi or 4x4-Low (in neutral of course)... I get some small click/thump noise... but the light in the switch just flashes.... and no 4x4 engagement in Hi or Low... which I've used recently.

The readout on the dash says "Service 4x4".

Looking for ideas?

Any common issues with these units?


ANY help is appreciated.

Thanks in advance.


.

 

[ndC7M8]

The switch on the dash has been the source of trouble on our past GM vehicles. I think only 2 pickups we ever had experienced that. Push the button, no 4WD, replaced the switch & it fixed it, granted these were half ton gas pickups. Try a scan tool if you have access to one to check it out first I suppose.

 

[mike_s]

A standard scan tool will most likely not tell you much. If you know someone with a Tech2 you can get in there and manually toggle the tranfer case without using the buttons and see realtime feedback. My suggestion would be find a buddy with the same body style (2002-2007 classic should all use the same) and snatch his switch (really easy to get out, dash bezle 2 screws and a plug), plug it in and if it makes yours work then you know. If it still acts the same you most likely have issues with the servo motors on the t-case itself.

 

[SRXSRULE]

The 2 most common issues are the push button switch on the dash and the range position sensor in the transfer case encoder motor. You can replace the entire encoder motor for 350ish dollars or remove motor, take apart and just replace the sensor inside it for 30ish dollars. GM sells both parts, I always do just the sensor if the motor functions ok. Saves the customer money and I make more money fixing it that way

Start off with scanning the Transfer case for trouble codes. Eric

 

[05900]

Fixed yet MH ?

 

[cowboy181d]

Simple fix my friend. Take her into a Gm dealer and have them reprogram the Transfer case encoder motor. Takes about 5 minutes including hooking up the Tech 2 scan tool. The click click pop noise your hearing is the over running safety clutch as the motor has lost calibration and the motor does not know where it is located in its travel. Don't let the service manager snow you into thinking it needs a encoder motor right up front (9 times out of 10 its a programming issue) and service desk riders like to sell parts and play mechanic.....

 

[mountainhorse]

Thank you all for the input... I had an appointment at the GM dealer... but tried it again this morning and it works for some reason..

Makes me nervous that it will let me down when I need it!



.

 

[SRXSRULE]

Makes me nervous that it will let me down when I need it!



.

Thats because it will

This issue can cause problems even when your not switching 4wd modes. It can cause the transmission not to up shift also. I would get it checked out sooner then later. It should still have history codes stored in the system. Eric

 

[AndrettiDog]

The 2 most common issues are the push button switch on the dash and the range position sensor in the transfer case encoder motor. You can replace the entire encoder motor for 350ish dollars or remove motor, take apart and just replace the sensor inside it for 30ish dollars. GM sells both parts, I always do just the sensor if the motor functions ok. Saves the customer money and I make more money fixing it that way

Start off with scanning the Transfer case for trouble codes. Eric

This is a great post. I wish I could have found it several years ago when I was trouble shooting the same thing. What I found is that my transfer case motor went bad. All the mechanic tools and websites said I needed to spend $350 on a new motor. But I did as SRX said and swapped just the board for about $40. It was very simple and fixed the problem.

 

[cgfire]

You need to get it scanned first to determine what dtc is stored and then go from there. Switches seemed to be majority of problem. Make sure it has current transfer case calibration. I can't recall changing any encoder motor sensors in the HD's. The encoder sensor was a problem with 1/2 tons with Auto Trak and 1500 HD with Auto Trak. Make sure grounds for transfer case system is clean.

 

[ullose272]

when in worked at the dealer we replaced a lot of encoder motors.

 

[AKtoad]

Encoder motor cost me an epic day of riding. I could not make it out of my driveway as my truck was stuck in 2wd.

 

[Indy_500]

I've owned an 05 and now an 06 Silverado both with service 4wd flashing across the screen. Both have needed encoder motor sensors. Easy 1 hr fix, can usually find them online for $30-40.

 

[slash]

a lot of times all you need to do is service the T CASE like most boxes the " oil "fluid
gets old breaks down and needs to be changed . I'm not positive but i think the owners manual says 24 k intervals