I replaced the box in my 80 GMC with a rebuilt one. That was a $250+ mistake. In less than 3 years, and less than 10,000 miles, it had too much play. Also, it began leaking where the steering shaft goes into the box. It was so rusted and crusty, that changing the seal was not an option. A friend had steering troubles with a used 79 he bought, and replaced the box, thinking it was the cause. He later found out someone put the pitman arm on the steering box upside down! So he was trying to find the old box in his shed to give to me. He couldn't, but suggested I buy a used box. He paid $100, and the box was "mint".
I called a local yard, and got one for $160. Not sure what it came out of, but it has no play at all. It's got 5,000+ miles on it from me now, and still no play, and no problems. I would NEVER buy a reman. steering box again.
I too replaced my box the first time trying to fix a steering problem, which in the end, had nothing to do with the box. I was kicking myself wishing I saved the old one, when the reman. one started leaking.
I kinda figure my box was 18 years old when I replaced it, and it was not leaking. It had play, but after 18 years and 130,000 miles, I would expect it to. Having the reman. leak after only 3 years, says a lot. Oh, and my 80 GMC came with a snow plow on it from the dealer back in 80, and plowed every storm since. So the front end was under constant stress, and saw miles and miles of 4wd use.