97 Blazer with push button 4x4. Just got this truck, starting to drive it on a regular basis. Today on the highway I could hear this sound slowly start to get louder coming from the front, possibly the pass. side. I slowed down right away, while driving slow it sounds like loud clicking. (Best described as like having a baseball card in your bike spokes) I pulled over, jacked up the right front wheel, spun it, didnt hear anything. Drove a bit further, I pushed the 4HI button, the sound went away. I pushed the 2HI button and all was fine for awhile. Seems to re appear at random.
I can say that while I drove in 4HI it made a random clunking sound, didnt feel like it was engaged in 4 wheel. (but I was on dry pavement) I'm afraid to try 4LO.

To get home with the truck, when the sound became noticable, I pushed 4HI and it went away, then went back to 2HI.

Also: All the lights on the pushbutton controller do light up. I've searched the other posts on here, Any ideas? Thank you!

 

the clicking sound puts cv in my head have you checked them

 

Either the CV or the Wheel bearing.....

 

Ok, I found a couple issues under the truck.

1. Passenger side sway bar rubber bushing ripped and half pulled out.

2. Both steering stabilzer links are missing the nuts. They were installed with the bolt coming up from the bottom, everything still there except the nut. BOTH sides, Odd that the nut fell off on both sides. I wonder who the hell worked on this before me...

 

If you put it into 4x4 and the sound goes away it might be the solenoid that controls the 4x4. That's what it was for me.

Doubt it's a wheel bearing as being in 4x4 or not doesn't make a difference.

 

Where is this solenoid located?

 

On mine I think it was down at the transfer case. It was 'sticking' so it never fully disengaged and kept clicking like two gears that almost mesh.

I'm embarrassed to say I had the dealership perform this repair as I didn't know what the cause was. Normally I do my own repairs so in this case I'm not 100% sure where they said it was.

Maybe someone else will chime in.

 

I'm fairly positive that this is a factory thing. I've had 3 Blazers thus far that have have sway bar end links that look like this. The only way I've seen to replace them is to cut them off. There may be another way, but sawzalls do work great.

 

No fix yet. Today I jumped in to see if it had fixed itself overnight. No luck...
Today it made the sound right off the bat. I pushed 4HI and back to 2hi and it went away, came back and did this a few times and after I was driving awhile it stayed quiet with no more noise. I would think its a vaccum issue if it did it instantly. Maybe driving awhile built up enough vaccum to keep it engaged properly? Seems like this problem came out of nowhere. I did see all the posts on how to diagnose 4 wheel drive. No luck yet. Thanks everyone

Would pulling fuse #19 for the 4x4 in the fuse box on the side of the dash stop the issue temporarily just to use the truck in 2wheel drive?

 

Pulling the fuse and turning the key on then reinserting the fuse may cause the TCCM to put the transfer case back into 2HI.