there is a T18A trans from a scout in the for sale forum and the 258 from a scout as well, is it better than the trans ihave in my 85 CJ7?? Do I need to swap transfer cases ??? I am thnking about taking the 258 as well, it is the same, no???

You have a T4 or T176 (4spd) or T5 (5spd), the T18 is a much stronger unit but it has a 6 spline output shaft and yours has a 23 spline output. Input shafts are the same, 1 1/8" 10 spline.
Might want to check if the output can be changed.
If you are taking the whole drivetrain, then yes you would get a stronger tranny.