Bought a lifted 95 1500 ext cab want to know what 2do with trans setup

Hello I am new to this forum and lifted trucks I do have much to learn, and I am Not new to engines and transmission so I do know quit abit

ok 1995 k1500 ext cab 350tbi
seems as though the np241c transfercase is popping out of 2wd into netural
also has a th-350 trans init? idk why the guys or guys before me did this?
all the wiring is still there from the 4l60e

so I guess the question at hand now is?
What will it take to get the 4l60e back into the truck? bolt in or has it been moddified to fit the th350?

also the t-case keep a 241c and will that bolt up to the 4l60e? or maybe go with a np205? will that fit?

Really looking to make this truck reliable again it is big and looks awesome
the lift kits are done right, and now looking to make the drivetrain reliable also?
Thanx