Brake shuddering excessively

[Gcelevator]

Hey guys, a question for the more experienced in the matter. I took the kids off roading (in their toys, not the Humvee) and while trailering and braking the truck started shuddering excessively, like never before. I have experienced shuddering in the truck and i know is normal, but this was a lot scarier. A couple of things that might have caused it (and i might be wrong)
1 - a slight oil leak in the right side front differential dripping on the rotor.
Solution: cleaned with degreaser and water, no change.
Cleaned with brake cleaner abundantly (2) cans. No change
2 - replensihed the brake reservoir with new dot 5 fluid.
(Possibly this?)

Worth to mention i never drained the brake fluid, as upon arrival it was almost new and no contamination signs.

What could be causing this? There are no other changes to how the truck has been driving or the maintenance to it.

 

[Retiredwarhorses]

Warped rotor
loose brake components

 

[Gcelevator]

Warped rotor
loose brake components

Steve, thank you for getting back to me. front rotors are new with new pads, less than 3 months old. i will double check for lose components but that is one of the 1st things checked while i was under the truck. i will doubles check everything.
i feel the vibration or shuddering coming from the front but i could be wrong and it could also be rear, rear are untouched.

 

[Gcelevator]

Warped rotor
loose brake components

I feel dumb now for not checking the rear brakes and asking stupid self explanatory questions. Issue found.