Clicking coming from Tranny?

When the engine is cold and I start it up, there is a clicking or almost like something is vibrating. It's pretty loud and getting louder each day. I thought it was a rod, but now I'm pretty sure it's coming from the tranny. It pretty much goes away once I drive around a while. I can still here it when I accelorate sometimes, but it's very faint. I've searched, and I all I could up with is maybe a cracked flexplate.? I was just wondering if anyone else has any ideas of what might be going on. Thanks.

'90 xj
4.0L
automatic

i would also check that the torque converter is not loose.

Ok, Thanks.