Like I stated earlier, 2003-06 tj/lj's use a Mercedes steering box. I had to change my box because the pitman arm shaft snapped right off the box.
When I did mine, I purchased the AGR box due to the expense of the PSC box. You can also use a stock style 97-02 tj box and several Saginaw type boxes but it does require modifying the frame at the steering box attachment point. It's not a big deal if you have a welder and some basic fabrication skills.
I opted to use the AGR box for convenience reasons.
Anyway, when I did mine, I removed and drilled out the lower steering shaft, so I could colapse it enough to fit.
I also had to bent the metal line on the power steering pressure line to get it to bolt up to the steering box.
After my install I had nothing but problems. My jeep was wandering all over the place, I had play in the steering and some other issues. AGR originally tried helping me by having me adjust the box, which did nothing.
They then denied warrantying the box because I adjusted it, at their instruction.
I eventually ordered the PSC box, The guys at PSC told me I could reuse the later style steering shaft by modifying it, but to do the job correctly I would need the earlier style shafts and power steering lines.
I would take a look at the lower shaft and see if he drilled out the plastic pin and colapsed the shaft. Maybe you will get lucky andfind that he swapped to the early style shafts.
This is from the PSC website, hope it helps.
https://www.pscmotorsports.com/pub/media/pdf/TJ_SG400.pdf
Here is the shaft that you want, if indeed your shaft is bad.
https://www.quadratec.com/products/56113_0010.htm