OK, so I have this problem. After a bit of searching throughout the site I have decided that it is more than likely an actuator switch on the transfer case problem.

Occasionally, while I am driving usually when either accelerating to or slowing down from highway speeds, I will get a weird sound that I can only describe as sounding almost like an air raid siren. As I slow down it gets lower in pitch. When I get to about 10-15 MPH there is a slight clunk and it goes away. I have tried shifting into neutral and revving it to see if it is engine related and there is no change. I have recently had the bearings replaced on both front sides, so I doubt it is that.

Also when I am driving around town I have noticed a slight clicking sound. I can only really hear it with the window down and if I drive past a building or something for the sound to echo off of. If I put the Blazer in 4hi or 4lo the sound goes away, but when I put it back into 2hi the sound comes back. This is what leads me to believe it is an actuator/vaccuum problem. If indeed it is an actuator switch, how hard would it be for me to replace? I am mechanically inclined. I know a little automotive-wise i.e brakes, oil changes, suspension. Would this be something that I can take care of myself, or should I have someone else take care of it?

If anybody has any insight/suggestions, I would gladly like to hear them as this issue is getting annoying.

 

I have experienced this noise in other s-series vehicles and in all cases, it was the vacuum switch on the transfer case. It would partially engage the front axle to the point where the gears would rub slightly until the speed difference was slow enough to lock it in.

I would say that your vacuum switch is bad.

 

Is number 41 on this page what I need?

http://www.lmctruck.com/icatalog/cst/full.aspx?Page=157

If so, would it be a simple enough job for me to take care of myself? BTW I am sure this has been asked before, but how do I get links connected to a word??

 

Looks like it. Any autoparts store should have it. It is a common problem. Although space is at a premium under their (ie there isn't much of it), it is fairly straight forward to replace.

Concerning hidden links, type out the word you want to have showing, highlight it, then click on the icon and paste in the url to the page you want to link to.

 

Thanks for the rapid response. You have no idea how much knowing the solution to this problem eases my mind. I will add the switch to my list of parts. I am still deployed to Iraq and I have been ordering parts and getting them shipped home. That way when I get home I will have something to do. At least for a little while.

I am still not seeing this link icon. Am I just blind?????

 

The link icon looks like the world with 2 links of a chain below it. Just to the right of where you select text color.

 

Check out the attached screen shots for the location of the link icon.

 

Rather than posting a new post for something along the same topic here I thought I'd just continue off of this post.

I drive a 95 s10 and the problems/noises i am experiencing seem to be the same. I believe it to be the vacuum switch. I followed what I believed to have been the vacuum lines back to the transfer case. I think i found it then coming down the drivers side and into the T-case. My question is, how the heck do I get it out? I don't think I can get anything in there to get it off and can barely get my hand in there.

Any ideas?

Thanks!

 

I just replaced mine the other day, I used a 22mm crows foot the looks like a line wrench. I used a 3/8 in drive ratchet on it. If you use your left hand and go in by the dront drive shaft you have a bit of room to work. I got it out with no problems. The top of the switch where the tubes connect is keyed so you can get them on wrong. It take a bit of patience to get it threaded back in. Once I got mine out I discovered it was stuck in the open position. I freed it up but put the new part in anyway. I figured if the old one stuck it might do it again. Now it works like its supposed to. Also check and make sure the actuating cable moves freely.

 

I'm not sure if I understand what you mean buy this. I haven't taken anything off yet because I'm skeptical as to whether I will get the hoses back on in the right spot.

Did you mean that it is keyed so you "can't" get them on wrong?