I have an 81 2WD all stock. 2 summers ago i replaced ALL the steering components sans the gear box. I also did the wheel bearings and brakes. Recently my truck has been steering quite strange, not sure of what a bad gearbox would present as. seems harder to turn and am getting some under and over steer. it tracks straight at highway speed. i checked and greased her up this weekend and all seemed fine.

any input is appreciated
also can these boxes be rebuilt?
Thanks!