Noise (clunking) When Engaging 4wd Hi/low

[06LS4X4]

G'day community. I'm the proud owner of a 06 Silverado Ext. I've noticed that when I engage my 4wd, the transfer case makes a clunking noise (the noise is more noticeable when engaging 4 wheel low). I've been to two local drive train techs, after theychecked my U-joints, they both told me that this noise is common for GM models. That doesn't satisfy me, however, so I though I'd take a friends advice and ask for peoples opinion on a site like this. The noise is even noticeable while driving if I take my foot off the accelerator while going up or down a hill, and then re-apply it.

If you happen to have the same symptom or have any idea as to what the problem is I would greatly appreciate your advice. Thanks in advance.

 

Cheers.

[Matt_]

The two clunks you're hearing are different.

 

The noise for engaging 4 hi and low is normal. That's the t-case engaging and 4low is more noticeable... make sure you're in neutral when you engage/disengage 4low. If you try to engage 4wd and you don't hear a noise... THATs when you need to worry!

 

The other noise you're hearing when you let off the gas is the infamous "gm driveline clink". There's a few TSB's on it... but none of them have been known to be a complete fix. You can try pulling off the driveshaft and putting some axle grease on the splines on the transmission end of the shaft... but that'll only quiet it up for a few thousand miles.

 

Eventually, i got used to it and forgot it was there.

[Daryl LBZ]

The two clunks you're hearing are different.

 

The noise for engaging 4 hi and low is normal. That's the t-case engaging and 4low is more noticeable... make sure you're in neutral when you engage/disengage 4low. If you try to engage 4wd and you don't hear a noise... THATs when you need to worry!

 

The other noise you're hearing when you let off the gas is the infamous "gm driveline clink". There's a few TSB's on it... but none of them have been known to be a complete fix. You can try pulling off the driveshaft and putting some axle grease on the splines on the transmission end of the shaft... but that'll only quiet it up for a few thousand miles.

 

Eventually, i got used to it and forgot it was there.

 

 

 

 

Ive heard the GM Drive Line Clunk so much that I don't even hear it anymore lol

[iamhistory]

Same here.......my '97 Silverado clunks like heck when I engage and disengage 4x4. Four low is much more noticeable than four high. The four high clunk is no big deal.

 

The noise you hear when you take your foot off the gas and then put it back on is something I have also. There is a amount of that and then I can tell when my u-joints are going bad. I can hear the difference pretty handily. If I am ever in doubt, I take it to my mechanic and he checks the u-joints out. I've only been wrong one time in the 9 years I've owned my '97.

 

I just bought a 2010 Silverado and I haven't really heard any noises in it yet. The 4x4 is relatively quiet, the driveshaft is relatively quiet, etc. The main noise I have in my '10 is the "my rear pass. door sounds like it's open" noise. It isn't bad but it is a tad bit annoying.

 

My wife's old '99 Blazer also clunked when going in and out of 4x4.