Knocking noise drivers side dash area on sharp impacts

[loopless]

2013 Outdoorsman 5.7 4WD 80K miles.
its been driving me nuts for a while. When the left front wheel hits a broken surface or drops into a minor pothole I get a knocking/heavy rattle under the dash. It’s seemingly coming from inside the drivers side dash area. It’s not the suspension which has been thoroughly redone with bilsteins ( no change to this issue, but made the truck 500% better to drive) and sounds too plasticky to be metal on metal. Could it be the steering damper being worn , seems unlikely at my mileage? I have got under the dash and wiggled everything I could find. It sounds like a substantial piece of plastic whacking something solid. Any suggestions greatly appreciated!

 

[BuschLatte420]

Loose intermediate steering shaft? Get up under there and try giving things a little wiggle. Sounds very annoying!

 

[Curmudgeon]

Remember that 10mm socket you lost?

 

[loopless]

Ok, so I solved this problem. The metal clip that holds the brake pedal on a metal shaft was not as tight as it should be, allowing the pedal to rattle over bumps. Of course the noise gets transmitted up behind the dash.