Z28LOVER

iTrader: (8)

I need help figuring out what may be wrong. Last year I had a custom tune done to my car and everything was ok but the past few months I've noticed that when my car shifts from 2-3 there is a thunk sound. I thought it was my torque arm bushing but i replaced it along with a trans crossmemeber with torque arm relocation. I recently installed a torque converter (3200 circle d) and I noticed the sound is much louder now. Could this be a problem with the converter or my trany? Also after the the converter install I noticed what sounds like a bearing going bad. When I first installed the converter I had some vibration so I put some shims in and it seem to cure that problem. Any info would be helpful and appreciated. Thanks