Electronic 4WD

[irondog]

My 2002 2500 wont come out of 4 low, tried unhooking battery, never worked. Its electronic and flashes like its gonna go to 2WD then just goes back to 4 low? Any ideas?

 

[x MadMAX DIESEL]

Dumb question, you are in neutral right


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[ty_LBZ]

IIRC, you can change it manually on the transfer case, using a 1/2" drive ratchet. Make sure you chock the wheels, you go thru neutral.

 

[DAVe3283]

I had the same thing happen after driving on pavement in 4LO for a while. Tried the same things (disconnect battery, etc). What finally got it to work was to idle slowly in reverse in a circle left, then right, then straight again. Put the trans in neutral, let it coast about 1/2 MPH, and it finally went back to 2HI. Strangely, it has worked perfect ever since.

If that fails, I do believe you can force it manually from under the truck, but like ty_LBZ said, block the wheels and/or set the parking brake, because getting run over is not fun.

 

[irondog]

tried everything, where on transfercase do i try it manually? And can it be donewith the front on jackstands and in neutral?

 

[ty_LBZ]

tried everything, where on transfercase do i try it manually? And can it be donewith the front on jackstands and in neutral?

I think it was on the manual shift transfer case it has that 1/2" square drive, where you can shift it manually. I just crawled under my truck just now and couldn't find it, mine has the electronic shift transfer case too.

 

[irondog]

Still cant get it out!! Any other ideas? I can here it but its not going out!!

 

[cwolfley]

hey there i had this happen to me last fall during hunting season, if i remember right just jack up the front end get both tires off the ground, then put yout foot on the brake and put in gear, then try and shift from 4lo to 4 hi then 2wd. i can remember the exact sequence but the front end gets in a bind sometimes and you have to get the pressure off it. also i have had luck just getting all the tires in the mud and going forward and back and it pops out. hope this helps good luck, your local gmc dealer service dept should be aware of this problem.

 

[irondog]

wolfley your talking the electronic 4wd? cause I tried with front wheels off ground it jus flashes and goes back to 4 lo!! im getting really frustrated!!

 

[DAVe3283]

Service Procedures

You might have had the shift motor on the transfer case fail, or something went wrong internally. It seems that at this point, you are going to have to start taking stuff apart.

I attached some of the service manual pages for your transfer case. If you want more, let me know, and I can post them up.

 

[irondog]

Ill I can hear is a buzzing noise down in the transfer case control module!! this is very frustrating!!

 

[irondog]

Does that mean its gone or what?

 

[ty_LBZ]

At some point your going to have to take it in or start tearing stuff apart. Nobody on here can pinpoint your problem from "a buzzing noise...is it going out?"

 

[irondog]

ok, thanks

 

[chevyburnout1]

A Tech II may be needed for any electrical diagnosis. However if the motor is making noise at the t/case the next easy step would be to remove the front driveshaft to make room to remove the electric shift motor, or 'encoder motor' on the transfer case. Pull the motor off, shift the transmission into neutral, then try to manually shift the transfer case with some pliers or other tool that wont damage the splines. If it physically wont move then there is something going on internal to the t/case.