1stDeuce

Ernie, if you're running bearings top and bottom in the knuckles, and you used some "Low Temp" grease to pack the knuckles, I think you might start elsewhere... First, the 80-90 in your steering box is thicker than peanut butter at -37 F. You might replace it with some synthetic 80-90 for a bit of improvement. See what that does for you.

Have you adjusted the preload in the steering gear lately? If so, you may have it too tight. The colder it gets, the tighter a given adjustment will be for a steering box, or at least that has been my experience. They certainly stiffen up a LOT when they're cold if you set them tight. You might back it off 1/8" to 14" of a turn...

Same might apply to knuckles... If the preload on the bearings is too tight, they'll start to seize up in the cold.

Man, I didn't think it was getting that cold anywhere yet... I feel bad starting stuff when it's below about -20F. And you're driving an M37 even colder than that just to have breakfast?! You have lost your hermit status for sure!!
C