4x4 clunking in 4L only
 

Hi everyone,
I just got a very nice '96 2500 4x4 with 100k on it.
There's what I think is a 4.5" lift and 31" tires, I was told the front axle was moved forward an inch and the transfer case was recently replaced by Dodge. Who knows if this is true.
I was told that the previous owner rarely used 4x4 and I believe that.
A friend called a 4x4 shop and they said that if a 4x4 isn't used much that it may make noises, I've only tried a couple of times (on dirt and slowly) the noise is so bad that I don't think it's just going to get better on it's own.
I don't want to influence the knowledgeable with my noobie opinion but to help describe the noise, I would say it feels like a gear is jumping or a chain is slipping with a jolt heard and felt quite strongly.
I've done quite a few searches and can't find my exact problem anywhere, mostly people seem to have problems getting into low or high or have noises in both ranges.
My problem is a serious clunking in 4L only.
4H seems fines.
Also the clunking seems to be mostly or only when the wheels are turned to the left usually hard left.
Thanks for any help.

sounds like an outter u-joint on the front axle

Thanks for the response, that could be it.
I tried again and I'm not sure 4 low is really engaging. I don't have much to relate it to since I'm pretty new to 4x4 but I can't tell in my very short test drives around the gravel/dirt yard that it seems to crawl more than 4 high. Again, I don't want to throw off the chase with my random guesses so take what I say with a pinch of salt.
i was reading a post where it was explained that if the popping was only happening while moving the truck and not while just turning the steering wheels then it had to be a rolling component like the wheel bearing I'm going to try that and see if might help eliminate parts. They were talking about 2 wheel drive so it might not tell me much.

there's a big difference between 4L and 4H !

change out your wheel joints

Well... today I got a little more aggressive in the dirt and things aren't quite as I initially described, hopefully this might help narrow things down.
When I switch to 4H the light comes on but I'm actually not in 4H, it's still in 2WD and the front wheels are not being driven. Or it really didn't seem like they were, I couldn't watch both front wheels but I was able to spin the rears and that wasn't happening in 4L.
When I go into 4L it's often a bit of an effort to get it in but sometimes much easier, I believe I'm actually in 4H then because there is no change in how fast I accelerate for the same RPMs as when I'm in 2H but the front wheels are being driven.
The popping is very much still there and it doesn't seem quite as isolated to hard turning of the wheels as I first thought.
I'd like to find some input on what I'm looking at getting into here. I understand transfer case rebuild kits aren't that pricey (if that's what I need) but what about axles or whatever else it might be? How hard is it to rebuild a trans case?
Are there upgrades that I should be looking into or aftermarket replacements? Do I need to tear into this first to see where things are at?
Again, don't let me lead your conclusions, I have no clue :P
Thanks for any help.

the clunking is 99% your u joints worn out...

BUT... can you put your TC in neutral ?

I'm 99% sure I can put it in neutral yes.
U joints can't stop it from engaging 4H and 4L though right?

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Also, if the clunking is u joints but only happens in 4x4 does that make sense?

do you have a straight axl?

I don't know