Comp. controlled 1987 700R4

will a 700R4 not hooked up to the computer and shifted with a 3speed shifter function hydraullically on its own?? Through 1st, 2nd and third.

Those transmissions were not computer controlled. They are all - hydraulic and will work fine on their own.
There is a 'throttle valve' cable that must be hooked up and adjusted properly.