Nasty clunking from mid/front when accelerating - Yukon Denali

[duffyboby]

Hi,
I have a newly purchased yukon denali that I got off my uncle, its a 2002 denali xl that he has owned from new.
Appart from the usual little things like broken manifold bolts and destroyed driver seat (lol) it has a very loud popping/skipping sound in the driveline from underneath when accelerating from a dead stop or accelerating at all at speed. My gut feeling is the chain inside the transfer case is skipping teeths (NP149 case) but I am wondering if there could be a common issue with the front diff that I dont know about that could cause that. It is defenately not a front axle shaft noise. Did anyone ever have the same or similar issue? Keep in mind it has been doing it for more than a year but he was only using it as a 3rd vehicle to haul bigger things.

 

[B-train]

I'd get the wheels off the ground and spin driveshafts by hand. See if there iss excessive slop from forward to reverse, etc. Check fluid levels/condition.

 

[vinbart]

A single pop? Or many popps? If single pop with each acceleration, it could be motor/trans mounts. Easy way to check -- pop the hood, sit in the car, start engine, put in gear, keep foot on brake, give it some gas -- watch the top of the engine from inside the car (should be able to peak under the hood)...if it hops up A BUNCH, you need new motor mounts, and prob trans mounts. I just did them on my 150k Yukon the other day.

 

[nonickatall]

I think there are four possible causes. Firstly, your transfer case. This can be removed, disassembled relatively easily and there are repair parts for it.
Or your front differential can also make a noise if something inside is broken. I don't know what exactly. But you can certainly take it apart and repair it or, if necessary, exchange it for a used one.
This can come as well from the engine mounts as already written by @vinbart
Or from the body mounts.

You will probably be able to tell yourself best, what the noise sounds like.

But it actually always makes the most sense to let someone else drive your car and you are driving alongside as a passenger in another car. You can hear than where the noise is coming from and you can usually hear very well whether it is coming from the middle below or from the front, to give you more information about the possible cause.

 

[OR VietVet]

Welcome to the forum from Oregon.

IMO, likely the transfer case or possible front driveshaft u-joint.

 

[duffyboby]

Wow I am amazed how responsive this forum is, thank you all for your quick response I was away from my phone all weekend, it does pop A LOT, @vinbart motor mount would make sense as I am currently doing the right exhaust manifold, it had 2 broken bolts. But theres no going away from the fact that the pops are LOUD, I'll order new mounts to do while the truck is up on the lift and mostly dissasembled. The ujoints are tight and there is no wierd binding when moving the driveline by hand in the air, and it doesnt make the noise up in the air either.

 

[09Magic]

I had similar noises from my 09 Tahoe. Turned out my motor mounts were toast. Like my engine was pretty much ONLY using gravity to stay in the engine bay. Replaced both mounts, now it's smooth as glass. I would go inspect those before tearing into the transfer case or anything like that.

 

[duffyboby]

Thanks, just ordered new ones

 

[duffyboby]

update: after changing motor mounts it is still doing it, i bought a transfer case and will report back

 

[tooleyondeck]

If you haven't already, check your CV axles while you're at it. I had a popping sound under hard acceleration and sharp turns that ended up being the result of a torn boot.