05 silverado switches to 4 wheel can't switch back

[bmklawt]

Hello

I have a 2005 silverado Z71 1500 5.3L
Most of these symptoms are intermittent and seem to occur when the truck is warmed up.
It feels like it is always in 4 HI even though the 2WD button is lit, sometimes I just find it in 4 HI, and when I do I can switch from 2WD to 4 HI, but to get it out of 4 HI I have to put it in auto then switch to 2WD. If I am having the above problems I can not get it into 4 LOW also sometimes when turn sharp at low speed it feels like its in 4 LOW.
Clear as mud, I can find no rhyme or reason to the symptoms.

Past threads mention re-soldering the wires to the switch, I am going to try that now but am hoping someone knows what the real problem is.

Your help is greatly appreciated.

[MT-2500]

Originally Posted by bmklawt

Hello

I have a 2005 silverado Z71 1500 5.3L
Most of these symptoms are intermittent and seem to occur when the truck is warmed up.
It feels like it is always in 4 HI even though the 2WD button is lit, sometimes I just find it in 4 HI, and when I do I can switch from 2WD to 4 HI, but to get it out of 4 HI I have to put it in auto then switch to 2WD. If I am having the above problems I can not get it into 4 LOW also sometimes when turn sharp at low speed it feels like its in 4 LOW.
Clear as mud, I can find no rhyme or reason to the symptoms.

Past threads mention re-soldering the wires to the switch, I am going to try that now but am hoping someone knows what the real problem is.

Your help is greatly appreciated.

Get a good transfer case capable scnner on it and run shift test and check for transfer case codes.
Post back code no.

[j cAT]

Originally Posted by bmklawt

Hello

I have a 2005 silverado Z71 1500 5.3L
Most of these symptoms are intermittent and seem to occur when the truck is warmed up.
It feels like it is always in 4 HI even though the 2WD button is lit, sometimes I just find it in 4 HI, and when I do I can switch from 2WD to 4 HI, but to get it out of 4 HI I have to put it in auto then switch to 2WD. If I am having the above problems I can not get it into 4 LOW also sometimes when turn sharp at low speed it feels like its in 4 LOW.
Clear as mud, I can find no rhyme or reason to the symptoms.

Past threads mention re-soldering the wires to the switch, I am going to try that now but am hoping someone knows what the real problem is.

Your help is greatly appreciated.

most likely it is a wiring problem ...since new has this vehicle had any drivetrain work done ? best check all undervehicle wiring around the transfercase / connectors etc..then get the drivetrain codes ..these codes will help locate the problem..

the switch failure , will get you a service 4wd light message ..

this could be the 4wd computer module but you must be sure because its expensive ..need code to be sure ,,,then some volteter work ..

[bmklawt]

OK I searched the net for a scanner but come up empty.
Am I looking for a specific scanner that can read the transfer case control module?
I can't seem to find on that says it reads transfer case codes. Please help.

[bmklawt]

OK can anyone help.
I am unable to find a code scanner that can read transfer case codes, can anyone recommend a scanner.
Also this problem seems to only happen after the truck has been driven for a while and it seems to jump into 4WD high when making a sharp turn a low speed.
I also found that when it is stuck in 4WD high and I press the Auto button the light on that button lights up but it still feels like it is in 4WD high always.
When it is stuck in 4WD high and I press the 4WD low or 2WD button that button will blink for a few seconds then will return to 4WD high, if I press the Auto button it will light up and from there if I press the 4WD low or 2WD button they will blink a few seconds and it will then return to 4WD high.
If I let the truck sit awhile all buttons work again.

Any help I can get on this will be greatly appreciated.
Bruce

[MT-2500]

Originally Posted by bmklawt

OK can anyone help.
I am unable to find a code scanner that can read transfer case codes, can anyone recommend a scanner.
Also this problem seems to only happen after the truck has been driven for a while and it seems to jump into 4WD high when making a sharp turn a low speed.
I also found that when it is stuck in 4WD high and I press the Auto button the light on that button lights up but it still feels like it is in 4WD high always.
When it is stuck in 4WD high and I press the 4WD low or 2WD button that button will blink for a few seconds then will return to 4WD high, if I press the Auto button it will light up and from there if I press the 4WD low or 2WD button they will blink a few seconds and it will then return to 4WD high.
If I let the truck sit awhile all buttons work again.

Any help I can get on this will be greatly appreciated.
Bruce

If a auto 4W transfer case you need a high end high dollar engine transmission transfer case scanner to get codes and do the shifting test.

Good one run 3500-5000 us$ plus 500 to 1000 $ a year for updates.

Snap on or gm tech scanners are the best.

For a one time deal cheaper to find a good repair shop that has the scanner and pay them 1/2 to hr labor to test it out for you.
Get the code and post back code no.

And as j-cat said check the wiring real good.

[bmklawt]

I brought this to the transmission shop and they tell me there are no transfer case codes, they said there are no codes for anything. They asked if anyone else had worked on it and cleared the codes, which no one has. I asked if they did shift test and he said they did.
I got under the truck and unplugged and plugged back in everything I could get my hands on and wiggled and jiggle all the wires and nothing seems lose or out of place.
I don't know what to do from here.

[MT-2500]

Is it still acting up like it was?
Was it checked for history codes?
Does service 4W light ever come on?

If not acting up now and no stored codes or history codes and no service 4W light wait until it acts up and before you shut engine off get it back on the scanner and see if it shows any problems.

Le us know how it goes.

[j cAT]

Originally Posted by bmklawt

I brought this to the transmission shop and they tell me there are no transfer case codes, they said there are no codes for anything. They asked if anyone else had worked on it and cleared the codes, which no one has. I asked if they did shift test and he said they did.
I got under the truck and unplugged and plugged back in everything I could get my hands on and wiggled and jiggle all the wires and nothing seems lose or out of place.
I don't know what to do from here.

not only is this problem your having weird , but the lack of transfercase failure codes is even more weird.

it is possible that the tranfercase module behind the 4wd select switch is defective or the connector/wires to it ..so check that all out.

[bmklawt]

The last time this was in the transmission shop they could find no problems but did take the actuator off and clean the connections, they said it might help

I have had this problem 3 more times since then, 2 of those times were on the weekend and again today. I was able to get it to the transmission shop today so they could see the problem.
They tell me there are no codes to read but they did said they tried to activate the actuator with there Tech II? and they couldn't get it to work until they key off and then on but the problem will return if you turn the front wheels hard while driving slow, they say the ABS is tied to this somehow and may be a contributing factor.
If you leave the truck off for 5 min or more the problem goes away for a long period.
They will but a new actuator on for $485.00 and guarantee the fix for one year, even if in the future it turns out to be the TCM.

Just to recap here is the problem, for future readers:
Sometimes after the truck is warmed up and I make a slow sharp turn the truck will shift into 4WD HIGH. I can not get this to shift out of 4WD HIGH, if I press the 2WD button it will blink longer than normal then go back to the 4WD HIGH button, if I press the AUTO button it will blink longer than normal and the AUTO button will light but it will still be stuck in 4WD HIGH, from here if I press the 2WD button it will blink for a bit then the 4WD HIGH button will light, I can not get it into 4WD LOW either.
If I leave the truck off for 5 minutes or more and start the truck back up it will be in 4WD HIGH but will shift normally then.
The transmission shop says there are no codes to read past or present and there are no idiot lights on the dash that light up.

Clear as mud.

[bmklawt]

On 9-02-2010 I had the transfer case encoder motor changed, the shifting problem has NOT returned.

[j cAT]

Originally Posted by bmklawt

On 9-02-2010 I had the transfer case encoder motor changed, the shifting problem has NOT returned.

this encoder motor can be damaged by going too long on transfercase TRACII FLUID changes. replace this fluid at the 30,ooomi point or when it turns from blue clear to gray in color........