I have seen lockup kits for th700r4's that are totally external where you don't have to pull the pan or anything. The one I remember well has a switch that mounts under the dash which, if engaged, guarantees lockup only in 4th (overdrive). It's made by a good company, B & M, and is like $75 bucks on the market. Then, Painless has an internal kit that is more than double the price but neatly installs within the transmission. Does anyone have thoughts about what works best?
