Vibrating Torque Converter

Does anybody with an Allison Transmission have the same vibration I do? I hear a buzzing noise, the truck surges, and I feel a vibration when the torque converter locks and unlocks. Any Ideas? Do I need a new torque converter, or is this just a common "normal" (according to GM) vibration?

I don't know about the Allison, but my truck had a vibration in it when it was about 2 or 3 years old when it shifted from 3rd to OD, and it was the converter going down, and GM replaced it under warranty.

Thanks for the input. I'm sure I need a new one as well, but its not under warrenty anymore. I will be doing it myself. Luckly there is an Allison dealer in town here, so it should be cheaper than GM. Has anyone pulled an Allison? and if so... is it a pain in the @$$? Is there some sort of elctric Torque Converter Clutch you have to take apart?

I don't know about the Allison, But on the 4L80E and 4L60E I have seen this problem solved with adding a bottle of friction modifier to the trans. My 4L60E used to do it and I addied the modifier and it solved it as did the neighbor on his. It may be worth a shot.