[denisond3]

I could imagine the cold (combined with normal aging) made the speedo cable really stiff, and that the parts that spin that cable might have snapped. There is a plastic gear inside the tranny that doesnt look too hard to damage, which also turns the Vehicle Speed Sensor.
The speedo cable plugs into the top of the VSS, which itself fits into the tranny, above where the passenger side axle shaft comes out.
This is a spot that is hard to get a good look at. Even after removing things to get to it, and taking out the bolt that clamps it down, the VSS will likely be hard to pull up - due to corrosion between its housing and the tranny case.
If that drive snapped and the VSS wasnt reporting 'movement' to the PCM, I can imagine the tranny staying in 1st. And of course the speedo wouldt work either.