possible bad torque converter??

[iownme]

Hi, 2004 X3 3.0, 110,000 miles

The car feels like there is a tranny problem, when you start driving there is a very slight hesitation before the car actually moves, and on deceleration one feels a "clunk" ...seems to come from the rear diff or driveshaft but as we know...sound travels..lol
Having read some forum posts i am thinking that the torque converter is bad. I went under the car to where the access hole is on the bell housing and when either reverse or drive is selected i can hear a rumbling sound coming from that access hole, the sound disappears when i select park or neutral.
When i select a gear from standstill, the car DOES start to move when i release the brake (without pressing the accelerator)
I doubt the car has ever had a transmission flush...is there any possibility that new tranny oil and a new filter might fix this...
any ideas welcome