Allowable backlash

Tore it down today and found that the shafts had worn into the case halfs, its junk.
I have had those repaired for me at the machine shop, I took 4 or 5 of them in one time. I didn't watched them do it, as it was several weeks before they were ready for pick-up. But it looks to me that they brazed it up with some hard yellow material, and then machined the saddles to fit the Good pins I supplied. I got a repaired one behind my 367HO that runs a manual and 295/50-15s. It's been in there for about forever? I think. That 3.55 has been following me around since the late 70s or early 80s. But I think I transferred in a repaired case in around 1999.The gears have survived at least 4 cars that I can think of. I transferred in the repaired case to see if it would survive, before I started selling the rest. Ima thinking I put about 100,000 on the repaired case now. I put another one in my 3.23s and another in my 4.30s both of which were long ago sold. I still got a couple kicking around. Hey that's 5 for sure already,lol.
So when you say junk; I think; only if it costs more to repair than what you would pay for new.
I don't recall what I paid, but it mustabin cheap, cuz that's the kind of guy I am,lol. If I had to guess; I don't think I would have authorized more than 40/50 bucks Canadian, apiece.