I have a stage 3 4L60E vacc. mod and a b&m trans cooler. What should the trans temp be at.

 

Not over 220*, if you can help it. City driving it can get hot. Make sure the trans fluid runs into the radiator first and then the tranny cooler, and not the other way around. In hot weather I hover around 165-180* on the interstate and around 210* in traffic, though it will work it's way up into the 230+ region if I drive around in traffic long enough.

 

cool, thats about where I am at now.