yup you're supposed to retorque them. In the book.
Or demand a new tractor and have the same problem again if you even get a new one.
Why do ya have to re-torque them? Because during manufacturing, they paint everything and I mean everything. Then the tractor gets assembled, using painted parts. Then tractor gets driven into a transporter after an inspection (and it's a pretty thorough inspection!!), transported to a warehouse, then to a dealer. Then it's sold. It's already assembled (BX TLB's are fully assembled at factory, minus a few minor things like unpackaging, pdi, etc). You take possession of it, you work it and during the time you're working it, the paint between the parts wears off and then the parts that are supposed to be clamped together become loose. Leave them loose and the attachment hardware breaks and the holes oblong. Pretty standard practice.
When a bolt is torqued, it is stretched. This acts as a spring to hold tension between the parts that are being attached with said bolt. The amount of stretch is little, measured in a few thousandths of an inch, or a few hundredths of a millimeter for the canucks and, well everyone else. The combined thickness of the paint on the painted parts that the bolts are holding together is much thicker than the amount of stretch on the fastener, thus when the paint compresses, chips, or wears off, the bolt(s) lose their springiness (clamp force) that holds the parts together, then stuff moves around-which is what you are seeing. Loader frames and backhoe frames take a huge load on them and their fasteners. If you check and retorque them at the first service per the manual (the manual that nobody bothers to read), you'll likely never ever have to touch them again. When I did dealer work, when I got a tractor in for first service (50 hr usually), that was on the list of things to "service"--tighten all the loader and backhoe bolts. I checked all bolts usually while fluids were draining. Those that say a 50 hour service is a total waste of money never had a good tech work on their stuff. Techs oftentimes find things that don't get documented on the repair order, thus the owner never knows about it--like loose loader bolts for instance. Hence, I personally bought my own laptop and loaded the dealer business system to it so I coudl document that stuff, which IMO was one of the things that made that dealer a great one (for the most part). Not trying to make myself look good, but it was one of those many litlte things that I did to help the customer. And to those that say techs are just grease monkeys? Shoe on the other foot....so why'd I leave? Hot shop, always pushed for time, boss too cheap to buy tools, kubota rep all over out butt about doing recalls that we didn't have tools to do, no raise in 7 years, I went in one day and said you know what I don't want to do this anymore...and left. Week later I had another job at another dealer, a/c shop, lot less work load, MUCH less stress, all the tools we need and boss buys tools if we need another, smaller, quieter, less dangerous, better pay, boss and I get along great....I mean, I had no choice but to take it!!