Take a look at the GM 700r4 it is a 4 speed auto. Low gear is 3.06 4th gear is overdrive @ .7 Now it can be used with or with out a lock up converter. I have 1 in my hot rod with a 3.73 rear, 2500 stall speed and the lock up. It will accelerate very good in low then cruise in OD with the converter locked. It works great for me. They use them in a lot of trucks and corvettes.