What transmissions interchange for 1996 Z71?

The factory uses the PCM / Powertrain control module to shift the transmission up and down. There for if it is a 1/2 Ton truck you will have to put the 4L60E transmission back in it for the engine and transmission will work right. If it's a 3/4 ton then it will have a 4L80E trans. in it.
If you don't want any troubles are head aches. You must install the factory transmission back in the truck.