I bought my 3861 Speedmaster new in late 2021. I wind it fully every morning and it is keeping perfect time. Just recently I have noticed that when winding it, as I reach full wind, on the last turn of the winder as the resistance to turning builds, there is a faint 'creaking' noise. It is as if the main spring creaks as the coils fully close. The watch is only 18 months old and working flawlessly, so I don't want to be sending it away for service just yet, but can anyone (Archer, perhaps?) assure me that this noise isn't a sign of anything seriously wrong? Thanks in advance. Stan.
Mine does that. Almost more felt than heard. It's from 1985 and features the 861 movement. It's just part of my Speedmaster's character and I've not been concerned.
Upside: you've got appx four more years for it to present itself as a real problem. That said, I believe you are fine and good to go.
If it's working flawlessly you don't have a problem. Never trouble trouble till trouble troubles you.