2011 Cascadia front end thunk noise when loaded?

My best guess would be check king pins and front bushings for starters.

 

Be sure to Grease the 5th wheel at least every wk. not having 5th wheel greased makes it harder for FT. end to turn, In snow and ice it can cause your truck to not be able to turn?

 

Leaf springs moving on steer axle could explain the thunk noise.

Not sure about the grinding you hear, maybe dirt or stones in your brake drum.

Good luck

 

Steer axle spring pin bushings are a good bet. Sit parked and move the steering wheel back and forth and listen for the noise, then try making turns at low speeds without a brake application and listen for the noise. If you're getting it in both scenarios, especially if you're not wandering all over the road while driving, check your pin bushings.
Other possibility is a bad brake return spring. Check that with a few service brake applications, whether stopped or moving, but make sure your steering wheel stays straight. If you have another set of eyes, visual confirmation is even better.

 

i have same problem. checked all parts and did not found the cause of sound.