fluid type for A-518

I can't imagine how +4 fluid causes soft shifts in non lockup transmissions. After all, the converter is not in lock up mode when they shift anyway.

Trans-go kit hands down. It's far more advanced than a B&M kit. Also note that the valve bodies are different on a 727 vs. a 518. The 518 main body is similar to a 727/904 but it has the o.d. control vb piggybacked onto it. If you've never done one before read the instructions at least 2-3 times before you even start. And if you don't have a blow up of the VB parts take pics so you get stuff back in right. One last thing, there is a mod you do to the rear servo to eliminate 1-2 shift overlap. It's a little tricky to do but it is absolutely vital for a good clean 1-2 shift and long trans. life.