when i put it in 4wd, it will start making a clunking noise, when i crank the wheels to the left or right it sometimes doesnt make that noise. but it seems like the 4wd works

 

Sounds like what Rcars2 had going on with his, it sounds like an actuater problem. His would clunk and not engage yours sounds like it clunks and engages.

 

my friend thinks that maybe a gearing is out or something, could he be right?

 

Hhmm.. mine sometimes makes the "clunk" when switching in and outof 4wd. Never really thought much of it though. So Rcars2 was an actuator problem?, or is that what he thinks? I mean is does obviuosly sound like a actuator problem.

 

Yes its an actuator problem you can clearly hear it when under the transfer case when he presses his 4wd buttons!!

 

Again, the sounds can be different, from a clunk to a click depending on the conditions. Every t-case is different. If the noise is repeatitive and is coming from the transfer case area, then the encoder motor may not be engaging properly until everything lines up right.

If it is coming from the front axle area, then I would say it is an actuator issue. It is possible that the actuator cable has some resistance that the vacuum actuator is having a hard time over coming. A bit of WD40 and some time and you can free that up. The actuator is located under your battery.

But please describe the problem in a bit more detail. Does this always happen? Does the clunking sound stay when in 4HI and 4LO, the entire time 4wd is engaged?

 

My dad's '93 Blazer also made a loud, "scary as hell" grinding sound he said when he tried putting it in 4L when he bought it. He immediately put it back in 2H and hasn't tried it again since. At the time he didn't try 4H. I told him to let me do it myself so I could try troubleshooting, but he says that he's afraid it might screw up totally if we do it again. I have no idea what transfer cases consist of. I know it's the manual shift and not the push-button one. Any thoughts?

 

betterlife18:
My 91 s10 blazer did the same thing when I first bought it. It was a crazy event, it would shake the whole truck and it would grind and jerk forward hazardly.. anyways, I found the front axle actuator/diaphram was leaking, so I replaced that.. and at the same time I replace the $18 transfer case vacuum switch, just because..(which supplies air to the front axle actuator), and now its good as new.. Although, it still grinds a little bit when shifting from 4H to N to 4L, but that is pretty normal.

 

ok here what happens, im in park and i press 4hi, it sound like it click in (dont know if it really but it does sound like it) and then i put it in drive, as i start going it make a clung noise, then just little less then a second later it makes another clung noise and it continue to make that clunging noise, if i go faster it does it more. and when i turn the wheel to the left or right about aquarter turnish it does not make sometimes. Then i try it in 4low but it seem like it makes a louderclungingnoise.the whole time i do it,the4wd works.one kid told me that its a bearing inmy front diff, myroommate dad told me itsound like its a cv joint. It only happens in 4wd. I really want to get this fix before i put on my 31s

 

Mostlikely is caused by the actuator not fully pulling the front axle engagement fork in. This could be a few different things. A problem with the cable that is causing increased resistance. A problem with the actuator that is causing decreased pulling power. Or a problem with the vacuum supply (leak, faulty/worn switch, etc) that is causing insufficient vacuum pressure to the actuator, resulting in decreased pulling power.

I would start by checking over the vacuum lines to the transfer case and back up front to the front axle actuator (under the battery). If they all seem in good condition, then I would feel how much resistance there is on the cable. You may have to disconnect it at both ends to check this and with it disconnected at both ends, it should move quite smoothly. If it does not, use some penetrating oil to lubricate the cable as you work it back and forth until it feels smooth and easy to move.

I highly doubt that you problem is in the front axle. These parts are fairly robust.