700r4 rebuild has problem! HELP!

[BFS57]

Hello;
I just had my 700r-4 rebuilt from a local builder that has a good reputation. First, the replacement rebuilt torque converter took a dump, right off!
After getting that replaced, the trans had this annoying whine coming when driving in 3rd!. After a call to the trans shop it was decided that they would replace the trans in the car completely! they did so and guess what, I still have the whine in 3rd ! They did say that the  2nd torque converter was not changed when they changed the trans for the last time.
Anyone got any suggestions to kind of let me know if I'm chasing my tail or what this whining sound could be?
I have drove the car in 2nd to test it and it doesn't have this sound. Mostly, I drive the car in traffic so I use 3 instead of O for this kind of driving and I really notice it then. When It shifts into O it seems to go away!?
This car is one of those un kind to "makeovers" kind of car that rebels against everything you do to it! I'm determined this car is going to get it's act together!

Bruce