2wd Disengaged Transmission while towing - have Autotrac

[the hammer]

This was scary/ nuts. I was moving to VA last week. during the tropical storm ( I brought it with me from FL). I realized i didn't want 4wd auto engaged so i put it in 2wd during the last part of the trip. I drove for maybe 15 minutes and all of a sudden I heard a loud clunk and my trannny completely disengaged with no gears engageable. Pulled over, pushed the auto 4wd button and everything went back to normal.

 

Followed up afterwards with just trying to drive with 2wd button engaged and it pops out of gear again without a trailer. In addition, I cannot engage 4wd Low at all, It just bangs three times and returns to either 4 High or 2 High.

 

Summary: drives fine with 4wdAuto button , but cannot drive with 2wd, 4 hi, and does not even engage 4wd Low.

 

Can someone point me in the correct direction of what to replace? I don't know if I have to buy the whole transfer case motot or if its just the actuator sensor inside. Please Help this sucks.

[gmtech4]

scan for codes first !!!!

 

do not jump to conclusions

[the hammer]

there are no codes, no warning lights, nothing.

[Chris]

Codes can be present without the light being on

 

Sent from my DROID RAZR MAXX using Xparent Red Tapatalk 2

[txab]

^{Make sure you check for codes with a scanner capable of reading other codes than just engine codes}

[the hammer]

There are no codes. I do not know what else to tell you all, the information I gave you is all there is. If codes are needed then we are out of luck.

[gmtech4]

then its mechanically failed ,the tcase has to come out and apart and an estimate for repair presented to you

 

good luck,let us know

[the hammer]

I hope you are not saying that simply because there are no codes. I don't jump to the conclusion that the case needs to be pulled when it is most likely the transfer case motor or the sensor inside the transfer case motor. Based on the analysis I have done and research on the web it is one of these two issues. I was hoping there was a specific way to test the sensor or the motor's sensor since there is no codes. Anyone know how?

[MikeNH]

I hope you are not saying that simply because there are no codes. I don't jump to the conclusion that the case needs to be pulled when it is most likely the transfer case motor or the sensor inside the transfer case motor. Based on the analysis I have done and research on the web it is one of these two issues. I was hoping there was a specific way to test the sensor or the motor's sensor since there is no codes. Anyone know how?

 

By using an advanced scan tool to communicate with the auxiliary control modules like the TCCM or whatever it's called on these trucks. And you still haven't clarified if such a tool was used to begin with as like others have said the lights can stay off and codes that are not readable by standard scan tools may be present.

[gmtech4]

do what ya want ,,,,,without a scanner to diagnose it ,you're just guessing

[the hammer]

Someone needs to clarify what type of advanced scanner you all are referring to. As of the OBD scanner you can plug in at Autozone and search everything for codes, I don't know where else to go without paying for a diagnostic charge. In that case, I would not be asking you all for help.

 

So, if there is something out there that I don't know about please tell me so I can get you the codes that aren't there with the OBD II. Otherwise I just have to take it to chevy and let them figure it out.

[MikeNH]

I seriously doubt the scanner autozone has can pull codes from auxiliary systems. You need to visit a dealer or find a shop with a high end scan tool, not the DIY places that check it for free with their scanner that probably cost $70.

[txab]

+1

[NitroCherokee]

Auto Zone scanner is NOT going to read codes in a TCCM, nor will there be any warning lights. If you want a guess as to what part to replace I suggest the dart board method. Or spend the 1/2 hour labor charge to have it scanned and diagnosed properly and save yourself a couple trips to the parts store.

[the hammer]

Ya I am heading to Chevy tomorrow. I will post up what they find.