Intermittent 4wd shift problems

[randyintahoe]

My 03 Silverado (Duramax) 2500 HD  is having intermittent problems shifting into and out of 4 wheel drive. I've spent way too many hours reading blogs and articles but I have come to realize this is a common problem! Because the system works some of the time and I'm not getting any "service 4wd drive" messages, all I have been able to do is clean off ground wire contacts on the frame and need to know what to do next! Sure would appreciate any help!

[Formulabruce]

This will fix your problem.

 In the early 200's GM started using a crappy type of solder to get rid of any lead solder.

This affected the control panel lighting, and the stepper motors on our trucks as most know.

This also affects the circuit board on the back of the 4WD switches.

Remove the dash bezel ring/cover, then pry out the switch.There are tabs holding it in place. Unplug the connector with a flat blade screwdriver.

 Pry the board out and re solder every terminal that's soldered. I use a tiny dot of soldering flux/paste, then a drop of new solder.

I have done many  with a 150 watt gun. it was fast .

 I have done this 5 times on trucks with same issue, even my own .

 Good luck !

[randyintahoe]

Thanks so much for your response!  Soldering is not one of my strong skills but I know "people"!  By the way, if I decided to replace the switch panel, do you think the new generation would be rid of the solder problem?  Again, thanks Formulabruce.

[randyintahoe]

Another question...with the truck  in 4 hi, I can hear movement in the transfer case area each time I press the 2 hi button and after many attempts, it will shift into 2hi.  Same thing going from 2 hi to 4 hi.  The indicator lights on the switches do their job every time. The switches seem to be calling for shifts every time but the shift is not completed. Is this consistent with your solution?  Thanks

[Formulabruce]

9 hours ago, randyintahoe said:

Another question...with the truck  in 4 hi, I can hear movement in the transfer case area each time I press the 2 hi button and after many attempts, it will shift into 2hi.  Same thing going from 2 hi to 4 hi.  The indicator lights on the switches do their job every time. The switches seem to be calling for shifts every time but the shift is not completed. Is this consistent with your solution?  Thanks

If the lights come on, It is probably Not the solution I mentioned. Are you moving when attempting the 4hi to 2 wd? I find I end up putting the transmission in Neutral if stopped takes any strain off the Transfer case shifter. Sound like the motor is workin, just sticking going in. AT -20 oF I have had it go a couple min before working if stopped. Moving, it seems to unlock the 4x4 easy. The T case has some wear points and can leak if the case gets worn, so check the fluid level.. Good luck !

[randyintahoe]

Thanks. It's a work in progress. Just had fluid levels checked and stopped off. I got all functions to work properly yesterday by repeating shift calls for more than an hour. It's as though a component in the system needs "exercise" to get working properly! I came back 3 hours later and the same problem returned...trying to decide what to try next. ???