Hello, I have a 99 grand cherokee limited with a 4.7 v8 4x4. It started making a knocking sound. It was faint at first and slowly got louder. It never lost any power though. I finally took it to a local repair shop. they told me it was a main bearing and I need a new motor. on the way home from the shop the jeep died on me and would not start back. I decided to rebuild it myself. I took the motor out and removed the oilpan to check the bearings and dont see any problems with them. any ideas what else might have made the noise.