96 Chrysler Cirrus Knocking noise

I have a 1996 Chrysler Cirrus, 2.5 liter V6, 153,000 miles on it. I have a knocking noise when I first start it up when its cold and will slowly quite after about a minute of running and it warms up. It will still knock when you idle it up or down. I believe I have tracked it down towards the transmission, converter area. But for the life of me I can not find out what it is. The engine starts and runs very smooth, so I do not think that it is an internal engine noise.