2007 1/2 ton Hemi, automatic RWD 120k miles

Morning folks! Got something that is rattling my brain and having trouble pin pointing the problem.

4 or 5 days ago I began to get a little vibration in the pedal/floorboard that gets worse as the speed increases, I can feel it from about 20mph+. I was driving with the window down and passed a parked car and hear what sounded like thin metal clanking, almost like a shovel lightly scraping the ground. Not so rough that it sounds like a gear grinding. So I did some driving with my head dangling out the window to figure out when it would happen.

When the truck is about to shift to second gear the sound of metal rattling comes in and once it has shifted into second it stops until the transmission is about to shift to 3rd and again it stops once its in 3rd. After 3rd I cant hear anymore because the truck/outside noise is tool loud. I cant really feel this in the pedal either only the steady vibration with speed.

The truck still runs and reacts normally nothing has changed in its drivability which really has me stumped.

I replaced the extension housing seal/boot and front U joint yesterday in hopes to eliminate the vibration and its still there. The front end I just replaced 6 months ago, new A arms, tie rod inner and outers, swaybar end links etc. New tires as well.

Thanks for reading! any advice appreciated.

 

What is the condition of the fluid? Check exhaust. Heat shields.

 

Fluid is looking great actually, still red and doesnt have any real smell to it. One of the exhaust shields on the passenger side of the block had 2 of the bolts snapped so i removed it completely, the rest of them are still in good condition.

I need a go pro or something to mount under the truck so I can try and isolate the metal noise I keep hearing.