Do you remember what if anything they did to those transmissions other than tune?We've had a couple guys use the 4L80e on 4bt swaps. So far, those seem to hold up OK. The 700R4 and 4L60e don't have such a good reputation. Don't know if anyone has used any of those higher numbers. Oldroofer and F100 Today are both using the 4L80e.