4x4 Acting Up

[ESSDOGHAULER]

Our 2003 2500 4x4 is acting up. When the ignition is on the 4x4 unit is switching between 2wd & 4wd Hi. If the system can't decide where to lock in it displays 'service 4x4'. I can hear it 'clunking' as it tries to switch and stay in 2wd. The switch position doesn't seem to matter and once it displays the error message it stops trying to switch.



I have tested the switch in the dash it is okay.



Any other troubleshooting ideas are welcome.



The truck has 86,000 miles, majority freeway. The 4x4 has been used lightly.



Thanks,

ESSDOGHAULER

 

[rbattelle]

The only thing I can think of would be to check the shifter motor itself. It could be burned out. Or maybe the electrical connector down there is corroded.

Ryan

 

[ESSDOGHAULER]

Hi Ryan,



Thank you for the suggestions, the motor is cycling as it is trying to kick into 2wd or 4wd but it doesn't lock in. Connector is clean and tight.



ESSDOGHAULER

 

[rbattelle]

This is a tough problem (as you are certainly aware).

Maybe the next level of diagnosis is to remove the actuator itself and have a look?

There is one other possibility - it *might* be possible to get more information using a DRB-III scan tool (dealer). There are quite a few diagnostic functions within the transfer case control module (electronic transfer cases only), and presumably one of these may be able to pinpoint the source of the issue.

Perhaps before pulling the actuator it's worth the diagnostic fee to let a dealer run his DRB-III on it?

Ryan

 

[dan.poitras]

Essdoghauler

I don't know where you live but maybe a member nearby has a DRB111. I picked up a factory one on E-Bay