I found that in experimenting. I was wondering if I could control the 3rd lock up better without a mystery switch. I don't have many miles on this trans at all but when I want to get on it in third I often go too far and loose TC lockup. I would like to be able to get on it hard at 40mph and get lock up but I don't very often it usually stays unlocked and doesn't pull as hard. I can get into it slowly and maintain lock up but by then I'm into OD TC lockup.
I guess maybe I need to drive it some more to learn it's characteristics. Then adjust a bit. The trans is solid shifting and night and day over a stocker.