4x4 help needed please!!!!!!
 

Hello everyone!! I am new to your site and its great to meet you all!! But I am in need of some serious help with my truck that makes no sense to me at all and may not to you, so here it goes.

I have a 2000 GMC Sierra 2500. I have been having a problem with the 4 wheel drive. When it is on a lift in a garage it works (4 high, 4 low, and 4 automatic). When it is on the ground, I have noting out of any of the 4 wheel options. But also, on the ground if I use 4 automatic, I get a message saying "Service 4x4". No messages in 4 high or 4 low. I had this truck to a dealer and they put an accuator in it, and it still don't work. Has any else ever had this problem? And how do I take care of it before I run it off a cliff? The place I bought it won't even take an initiative to fix it saying it is not there problem. Another thing, you can hear and watch the transfer case engage. But it does not matter if you are on mud, sand, stone, etc. It will not move all 4 wheels like it should, the back ones just spin and not the front. Any and all help is greatly appreciated and thank you in advance very very much!!!

Welcome to the site! If you are on solid ground and put it in 4 wheel do you feel it lug and when you turn do you feel it skip. There is a motor on the transfer case - is this what was replaced?

Thank you so much for the welcome Mr. Shamrock!

The truck does not lug when you hit 4 wheel high, but you can really feel the entire truck jolt when you hit 4 low with the truck in drive while holding in the brake pedal. As for the skipping, none. The said they replaced the 4 wheel drive actuator in the front end, if that sounds right. I was also told that this make, model, and year the transfer case is set up like an automatic transmission and has it's own clutch. And that the clutch in the transfer case might have went bad. Never heard of that, but then again, this is the newest truck and 4x4 I have ever owned. Like I said, you can be on any type of ground and it don't matter if you put it in 4 high, low or automatic, and gun it or take it easy, you get nothing out of the front end. You can hear the transfer case engaging, and watch it engage, but you have absolutely nothing from the front end.

If you are on solid ground with it in 4 wheel drive and make a turn -especially a tight turn it should jump, skip, or whatever you want to call it. You should definitely feel something. It may be in the switch on the dash and it is always going into Auto 4 wheel drive so it won't do anything up front unless the rear doesn't have traction and that would explain the front turning when on the lift. Those switched go out alot. I would check it first.

I'm sorry, I updated my post as you were typing I guess. Another thing that gets me though was when the back starts spinning, I still have nothing out of the front tires.

Do you know anyone with the same truck that you could swap switches with just to rule that out? I have seen them act up and do some real weird things. Besides that it really doesn't make sense to me either. It's either engaging or it's not.

I can check. Does it have to be the same year for the switch?

No just make sure if yours has Auto 4WD like you have indicated that the test switch has it as well. Not all of them have the Auto function. Good Luck!

Thanks alot!!!!! I think I'm going to need it.