phoenix is one of the best out here, but they do not list the 6l80e, and from what I have dealt with, if it isn't listed, they don't deal with it. North Texas Converters, Jake's Performance, and someone else who I can't recall doesn't rebuild them either. I looked at PATC, but decided to stick with Futral. FLT I did not look into. Didn't think of them, but in the past, I've heard bad things.