wierd sound randomly started

K, so i have a 1990 cherokee 8 inches of lift with my long arm kit and crossmember, 4.7 stroker, AW4, NP231, 35" KM2s. Now all of a sudden out of nowhere as my girlfriend was pulling down a bumpy gravel road it started making this sound, kinda like when pushing a shopping cart with a loose wheel over bumpy asphault. I cant figure out for the life of me what it is. Doesnt start making noise till about 20 MPH in gear, out of gear, or engine off and coasting, or even in 4 wheel. My front driveline is currently wired up to the frame because I need to replace the driveline yoke but I know thats not the noise, its wired tight with bailing wire and when I put it in 4 wheel it makes a noise of course.
I have been leaking tranny fluid out of the t case seal at the slip yoke, could the lack of fluid be it? Or something as simple as gravel in the center wheel caps? lol

Thank you for any guesses or ideas.
Kris Froehlich

Oh, and everytime I hit a decent bump the rattling is amplified for that split second then returns to the consistent rattling which is why I dont think its the t case or part of the drivetrain. I would think it would stay consistent bumps or not. Also, there is currently no exhaust after the header on this vehicle either.