New flex plate, knocking noise still!

I have a small knocking noise at idle. It is definatly at the bell housing and it isnt a rod knock. you can hear it only if your in the jeep or on standing next to it, if your in front of it you can't hear it over the motor. The jeep runs great. it is very faint and it gets a little louder under a load or when accelerating so i checked the torque converter bolts and they where tight. So i drove it like that with the small knock. So it lead me to believe it was the flex plate was cracked. so today i took my trans out and replaced the flex plate. my old one wasn't even bad other than the torque converter bolt holes were a slightly rounded. So i put the new one on and hoped it would work. the noise seemed to get quieter but is definatly still there. could the TQ be the cause of the noise? I am running out of ideas on how to get rid of the noise, anyone have any ideas? I'm just sick of my perfectly good truck sound like it has a rod knock. Any advice would help Thanks