Steering problem

[GSFMECH]

I know this is not for a 67-72 but for a 98 Z-71. All you guys know a lot about Chevy trucks so I thought I would post it here as well as 88-98 board. Does anyone know if a 2wd steering box is the same as a 4x4. My 98 Z-71 has lots of slack in the output shaft, it looks like a bushing or something is worn out and it drives like crap. I have changed out the sensor and pitman/idler arm in good shape. I have access to early 90's 2wd box and also a 3/4 ton box, both in good shape. The 3/4 ton box is real nice. Was wondering if they would fit. It looks like a tough job as it is a tight fit. Thanks in advance,
Mike