Kerclunk from front diff

[mikehummer69]

I went wheelin the other day up in the mountains. The road was wet and muddy. I didn't need to be in 4 wheel drive the whole time but i kept it in 4High anyways. While climbing a moderate slope the front end went clunk, then kerclunk, silence, then another clunk. I eased off the gas and it clunked again. I came to a stop and started again, another kerclunk. I shifted to 2High and started again, no clunks. When I got to the next flat ground a stopped for a break and to check under the front end. I looked at everything the best I could (there was sticky mud everywhere) but couldn't see anything of obvious mechanical problems. I was wheelin alone (except for my worried wife in the passenger seat) no other truck to pull me out of a jam, so I opted to turn tail and return down the mountain in 2 wheel drive. When I got to my driveway I shifted into 4High while pulling in and kerklunk again.
So, there's no problems in 2 wheel. It klunks in 4high, I haven't tried 4low yet. The fluid is new and up to the fill hole. Is it the front diff? or maybe a CV? I thought CVs clicked not clunked. I did take both the CVs off my parts truck because my boots were torn. I don't know the condition of them because the parts truck wasn't running when I aquired it. If it's the differential would it be an easy fix? I do have the diff on the parts truck if it came to it. I am mechanically inclined. I just haven't had this happen to me before.
Any thoughts, problem solvers, fixes, or ideas would be greatly appreciated.

[King_Ice_flash]

Put it up on jack stands and turn everything.

does it make noise when you take a sharp corner?

[ShowNgo4fun]

My guess is...you busted something...something important. Glad I could help!

[Blazer69]

could easily be the cv axle.

[mikehummer69]

The CVs don't make any noise at any time. I haven't had a chance to do anything to er yet. I will have to soon though, the snow keeps creepin down the mountains.

[Korban_Dallas]

I'll Refer you too my Thread here:
http://www.s10planet.com/forum/showthread.php?t=16388

Your Issue sounds just like mine did, I would say stay out of 4WD cause if it is the same issue your Metal on Metal at this point... what you can try and do is drain the fluid and stick your finger in the drain hole and see if you can feel any plastic chunks inside the hole (The Pump Pickup is right by the drain hole) but I did not even know about the plastic until I took my Transfer Case apart when I did the Fluid Change I did not see anything in the fluid out of the ordinary when that plastic comes apart the gears pack that **** in all the small crevices in the Transfer case so it's really hard to know if that is the case until you take it apart.

And yes my thinking was the same as yours (CV Joints) I replaced my RF and LF and the one on the Front Drive Shaft and that did not fix it, I also took the axle shaft out of the RF side cause I screwed up the engaging part of the Diff. because I left a vacuum line off from under my Dash (dumbass move) but that noise was like a growling noise the Clunk is from the Transfer Case.

[Blazer69]

the engaging part is a pita. i had the all data on it and was about to fix mine and it turned out to be the vacuum switch on the transfer case.