If electrical, it could be the TCCM (passenger side kick panel) or the Encoder Motor (side of transfer case).

The TCCMs in these trucks like to corrode the connections which can cause all kinds of weird problems.

The Encoder Motor likes to be real finicky about positioning and the position sensor is not that accurate to begin with. The problem really centers around the position sensor, but because it cannot be replaced separately, the encoder motor must be replaced (last resort). Since you do not have the Auto4wd feature, you can run through checking the codes as described in the DIY article (forgot the name of it, but I think it is on pg 3..

 

Swartlkk, let me tell you this......YOU ARE THE MAN!!!!!! LOL

So I just got back from a drive, and I did what you said. I shifted into drive, and then went from 2 HI to 4 HI. I was on a small slope, so I shifted into Neutral, and then pressed 4 LO while still moving very slow.

IT WENT RIGHT IN WITHOUT ANY BLINKING OR ANYTHING!!!!

Thanks a lot. The only thing I highly regret, is being too impatient to get it fixed, and going to the Chevy dealer and getting ripped off big time. Let me tell you, I love Chevy, and I love my truck to the fullest, but I can't believe how the dealer rips you off like that. To me, they are thieves. The guy told me about $500 to open up the transfer case, and then $400 just do some fluid exchanges on the differentials? I think that the only time I'll be going to a Chevy dealer again is to buy an original part, not for service. There was an elderly person that was in the waiting room with me, and the counterman came in and told him that he had to order a rim and some tires for him. HE ALSO MENTIONED THAT HIS BILL WAS GOING TO BE $985? MY JAW DROPPED WHEN HE SAID THAT, AND IT'S NOT EVEN MY BILL. LMAO

But again, thanks for helping me out. To me, you are one of the best after seeing that not one mechanic, but one mechanic and the techs at the Chevy dealer could not find the very simple solution.

 

Glad to help!

Do you still have the whirling/clicking sound??

 

Yes, unfortunately, that problem is still there. I really don't know what it could be. Although, let me tell you this. I had recently had a control arm replaced, along with the steering gear box. My mechanic was not able to do the wheel alignment for me along with this, because his machine had to be fixed at the time. So I decided to take it back to Sears, where I had purchased my Bridgestone tires. I was up for a free tire rotation, and I also had them do the alignment. As soon as they handed me the keys, I took the truck for a spin, and noticed that it was still pulling to the right. So I immediately went back to them, and they told me that it was because I had different thread depths on each tire. They said the only way to fix that problem was to buy new tires. I couldn't believe it, and I had no choice but to leave it. For some reason, I am believing that they did a bad job with the wheel alignment. But I am not sure if that is exactly my problem.

I had made a previous post, about this humming sound, and I think that you were the one that replied to me. It was about this same humming/whiring noise. I thought the wheel alignment would take care of it, but either Sears messed it up, or the wheel alignment didn't solve the problem. The reason why I mentioned the whiring noise here was because I thought it was related to the problem I was having with my 4wd.

But I do know that I still have to keep the steering wheel turned very slightly to the left, in order to keep the truck straight, because if not it goes slightly off to the right.

 

Sorry for taking so long to get back to you... A failing vacuum switch at the transfer case can cause the front axle to remain partially engaged. Also, a sticking engagement cable could cause the same symptoms. I would check for free operation of the actuator cable and also check to see if you have vacuum at the actuator when the transfer case is in 2wd, engine running. If you do, the switch is bad.

 

lol It's alright. I haven't been on here in a few days. I might just go ahead and replaced the switch on the transfer case. But is there another way to check if the front end is partially engaged, with having the truck on a lift, and just seeing if any wheels or shafts turn?