Yeah exhaust leak is the first place so check the connection at the head pipe to exhaust manifold. Other ticks associated with speed and are constant is the T-Case chain slapping the outer case. You may have something stuck in the u-joints in the front diff. It could also be something stuck in the dust shield around your disc brakes. And then it could be a u-joint on either shaft.
89YJ 2.5L TBI, AX-5, NP231 SYE, Ford 8.8, Yukon Grizzly, Tom Woods Shaft, 33" BFG T/As, 4" lift, Warn VR10000s.
AF Jeep Club Tail #184