Shifting “thunk”

[optimusprime]

Also, maybe to narrow it down, it is most pronounced when coasting and then giving it throttle. There is always an audible clunk but it gets louder with greater speeds

 

[iamdub]

My biggest concern here is that since you had no idea of what this process was, I am worried about telling you to crawl under the running rig and torque it in gear.

Yes! This is why I suggested he drive it as usual, but jab the throttle from a stop. He'd be able to hear whatever sound he's hearing and in the same manner that he's been hearing it- in the cabin, doors closed, etc., and get a more accurate comparison.

Some don't do the "powerbrake" test very well. They hold the brake and gently ease into the throttle, which does nothing. Or, they don't hold the brake enough and goose the throttle and almost make a carport out of their garage.

Watching the engine through the gap at the back (bottom?) of the open hood where it meets the cowl is "stage two" of testing the mounts after they've proven themselves by successfully completing the road test. Safety is of utmost importance to the TYF fam.

 

[iamdub]

Also, maybe to narrow it down, it is most pronounced when coasting and then giving it throttle. There is always an audible clunk but it gets louder with greater speeds

Unfortunately, this is now starting to sound like something more than a simple/common engine mount. But, we still gotta start with the basics.

 

[Doubeleive]

Thanks for the info. I’ll check the slip yoke too. For what it’s worth, when I shift the truck in reverse and drive, there is an Audible clunk coming from under the truck. Been doing that since 2016.

some light clunk noise is normal, you may notice it more if you park on a slight incline.

 

[Fless]

As @iamdub suggested a while back, don't forget to check the U-joints in all of the driveshafts.

 

[Geotrash]

Also, maybe to narrow it down, it is most pronounced when coasting and then giving it throttle. There is always an audible clunk but it gets louder with greater speeds

I have the exact same thing in my ‘07 Denali and my motor mounts are new. But I do have a bad front differential mount that I’ve been too lazy to change, and a ton of slop in my transfer case chain. My u-joints are solid, so it’s possible it’s either the front differential mount or the transfer case in both of our trucks.

 

[Joseph Garcia]

I had a very similar clunk. I changed the slip yoke, and no difference. It ended up being the front differential mount bushings, so I changed both mounts brackets, including new bushings. Clunk gone!

 

[donjetman]

Our 07 awd Denali does it too. I believe it a combination of worn components, but mainly a wornout/loose transfer case chain(167k miles)