i have a loud pop coming from front axle in 4wd only. what could be causing this

i hear u, pushrod, all i can say is that the "pop" feels like its in the front right axle/hub area, and its intermittent. i recently replaced the ball joints/tierods but the noise is still there. im just hoping to gain some insight before resorting to takin it to the shop. thanks for the help. i should mention its got 6"lift from tuff country & 33" tires but the cv angle looks ok.

I got the 'while in 4x4 only' part but .. When does it make the noise .. What action is being taken, turning wheels hard left or right while in motion? .. Taking off or stopping? .. Hitting a bump - pothole? .. Drivetrain under torque or freewheeling? .. These are just some of the things that must be considered .. Front u-joints .. Cv -joints .. Ball joints .. Hub bearings .. Front differential gears.

ok it usually happens on takeoff when its under load, meaning either uphill or thru mud. it seems to be fine on flatter surface or downhill. i also have done both front hub bearings recently without any affect, good or bad to the noise. thank u for your input, i really do appreciate any & all. Also, its not necessarily during a turn, happens going straight forward.

How about if you 'brake check' it? .. (Rev engine with trans in gear - brakes on) .. Can you make it do this with truck sitting still - in drive or reverse? .. OR maybe shifting 'from' reverse to drive & back?

that's a good question, ill have to try it later on. is that a way to tell if the prob is suspension related vs drivetrain?

IF the noise can be duplicated with truck motionless, the problem is MUCH easier to find... Can be hoisted on a 'drive on lift' for inspection with driver in cab brake checking vehicle.

Thanks brother, will update asap.

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Hello I have the same problem you have. Did you find the problem? I’ve replaced the front cv axles, front shocks, Sway bar links, flushed the front differential, transfer case , and transmission. I also replaced transfer case shift motor. But it hasn’t fixed my problem. I have a 2001 Chevy Silverado HD 8.1. Only happens in 4wd going up a hill. Just like yours it sounds like it’s coming from the front right side.

Thanks for the input, I really do think its coming from the front right axle/hub area, but I will look into T-case chain. Any idea of how i can test that at home? (if even possible) Also, if it was the chain would it be limited to just a single "pop" noise or more of a rubbing kinda thing? Just wondering, thanks again..

Did you find the cause of the sound?

Hey tremolo, i haven't been able to do much w the truck, i will post an update asap. is your truck a 2500hd?

Thanks for responding. Yes I have a 2001gmc Sierra2500hd 8.1liter. The description that you gave was exactly the same as mine. The sound yesterday was louder than I've ever heard it. It was a loud pop, or clank. It always seems to come from the right front side when driving. We depend on our 4 wheel drive and now im concerned we will become stranded. I'm too afraid to use the 4 wheel drive after the loud popping. Hey, I have also had issues with something draining my battery. I have to buy a new battery every couple of years. Have you experienced this? Thanks. I appreciate any advice you can give. Thanks again.

Hello have you found a fix to your problem.??