4WD not working but no Service 4wd light

[rockola1971]

So if I don't hear the actuator that would mean it's the problem? I haven't heard the actuator moving at all, the only thing that changes is the light on the switch.

Your 4wd dash light will NOT change if the encoder ring isnt reporting back commanded (You pushing the buttons) position wasnt completed. The commanded position is put in motion by the shift motor (AKA Encoder Motor). So your shift motor is fine and there is no way any of your dash 4wd indicators would change without it working correctly.
Your front driveshaft is either not turning because of an internal failure of the Tcase (Tcase chain) or your front driveshaft is turning under Tcase power but your front axles arent locked in because of front actuator problem (either mechanical or electrical).

Needs to be put on a lift to find out which and troubleshoot from there.

 

[Doubeleive]

I would suspect the actuator, if it is not working usually it should give a code/error or service 4wd on the display but maybe not in this case
I think they run about $150-160.00

 

[rockola1971]

I would suspect the actuator, if it is not working usually it should give a code/error or service 4wd on the display but maybe not in this case
I think they run about $150-160.00

Wanna bet? Ill bet you a set of OEM Spark Plugs. And ill need my plugs for a 05 Yukon Denali 6.0. AC Delco!

When the shift motor doesnt goto commanded position the 4wd light flashes and stays like that until 2wd is pushed or vehicle is shutoff and turned back on.

 

[Doubeleive]

Your 4wd dash light will NOT change if the encoder ring isnt reporting back commanded (You pushing the buttons) position wasnt completed. The commanded position is put in motion by the shift motor (AKA Encoder Motor). So your shift motor is fine and there is no way any of your dash 4wd indicators would change without it working correctly.
Your front driveshaft is either not turning because of an internal failure of the Tcase (Tcase chain) or your front driveshaft is turning under Tcase power but your front axles arent locked in because of front actuator problem (either mechanical or electrical).

Needs to be put on a lift to find out which and troubleshoot from there.

I agree with this guy you need to at least put it on 4 stands and see if you see what is happening, you may also be able to unbolt the actuator and have someone hit the buttons and see if it is moving position or not

 

[Doubeleive]

Wanna bet? Ill bet you a set of OEM Spark Plugs. And ill need my plugs for a 05 Yukon Denali 6.0. AC Delco!

When the shift motor doesnt goto commanded position the 4wd light flashes and stays like that until 2wd is pushed or vehicle is shutoff and turned back on.

it should be giving a code or rejecting the command, but I've seen stranger things happen.....

 

[Doubeleive]

Your 4wd dash light will NOT change if the encoder ring isnt reporting back commanded (You pushing the buttons) position wasnt completed. The commanded position is put in motion by the shift motor (AKA Encoder Motor). So your shift motor is fine and there is no way any of your dash 4wd indicators would change without it working correctly.
Your front driveshaft is either not turning because of an internal failure of the Tcase (Tcase chain) or your front driveshaft is turning under Tcase power but your front axles arent locked in because of front actuator problem (either mechanical or electrical).

Needs to be put on a lift to find out which and troubleshoot from there.

and that was was my first thought is the front one isn't engaging, that one is cheaper and easier to replace.

 

[Doubeleive]

front

 

[rockola1971]

it should be giving a code or rejecting the command, but I've seen stranger things happen.....

Why would it give a code if the shift motor is going to the commanded position? It wouldnt because its doing exactly what its suppose to be doing. The 4wd module has no way to tell if the front driveshaft is being powered by the Tcase. If there is an internal mechanical fault like a busted or loose chain then the 4wd module will NOT know this has happened. All it knows it that the transfer case was commanded into 4wd Hi and the shift motor physically put it in that range selection successfully after the button was pushed.

 

[Doubeleive]

Why would it give a code if the shift motor is going to the commanded position? It wouldnt because its doing exactly what its suppose to be doing. The 4wd module has no way to tell if the front driveshaft is being powered by the Tcase. If there is an internal mechanical fault like a busted or loose chain then the 4wd module will NOT know this has happened. All it knows it that the transfer case was commanded into 4wd Hi and the shift motor physically put it in that range selection successfully after the button was pushed.

I agree with you I was confusing the t-case actuator with the front actuator and got side tracked to the t case one, lol

 

[rockola1971]

I agree with you I was confusing the t-case actuator with the front actuator and got side tracked to the t case one, lol

It should take longer to put on jackstand or a lift than to see if the driveshaft is turning or not while in 4wd hi. That will tell whether problem is in the Tcase or up front in the front actuator. Shouldnt take but a minute or so...while chewing gum and blowing bubbles.