Interesting point about stripping the gears as a safety feature, that was my concern about going for the brass replacements (however I have just ordered a set!). I have cleaned what I can and the butterfly operates smoothly without jamming, So hopefully that will not be a problem for several thousand miles. I would assume that the motor would stall if a jam occurred but that might burn the motor out.I would not take the butterfly off the shaft. Diesels run on full air all the time so greater chance of the screws vibrating loose and being eaten by the engine. On your gear train is there too much missing or can you relocate the meshed gears again to allow full travel? Difficult to see exactly from your picture but suspect that gear is no longer useable. Plastic gear teeth are used as a designed failure point, if the butterfly is stuck then the gear teeth get sacrificed saving the motor or mechanism. Brass gears will last longer than plastic but you have immediately remove the protection element of the sacrificial plastic teeth. Would be more inclined to fit a clean and tested used ASV provided the mounting points and physical dimensions are the same as the A2 unit.