Well, -40 is pretty cold but I would bet that most motors could handle it baring any major blowing of snow into the components that might melt and refreeze. I know my sg2100 did just fine last year, but it didn't get quite that cold temp wise. Wind chill wise there were only maybe a couple days like that. Where are you at that -40 is a common temp?
Dang isn't -40 the same on both scales? I think that is the one temp that is the same for F and C.
Ive never used any of my sat equipmet at that tempetures but I will say from experience that at -45c plastic doesnt fare well and can crack easily. I might wana go for a stab as the sg2100 has a plastic final gear.
Manitoba winters haven't fazed my SG2100. Its been though three of them turning a 33 to 39" dish and handled some pretty good winds. Some plastics might be good in cold from the perspective that they are self lubricating and don't need grease. Grease can become like wax / glue at cold temps. Never taken one apart, so I have no idea if they have greased bushings, dry bushing or roller bearings. It still moves accurately as well. Not developing play in the arm.