I hear a noise that I am trying to pinpoint. It has been like this for 40k miles, but I now want to get to the bottom of it. When the 4runner is warm and in drive only, idling I get a knocking noise. It seems to be coming low in the engine or transmission area. It is not the top end. My father owned the vehicle before me and I have records since new. I thought it might have been the crankshaft pulley so I bought a new one and torqued it to 218 ft lb. The noise does not happen when in park or if the engine is cold. I have a limited 4wd with the 3.4l v6 engine and I'm at 173k miles now.