1998 XCV70 auto tranny issue, help me understand

[xHeart]

Weep hole at the water pump is a familiar place.
Radiator drain petcock stands out after looking, but a weep hole at the intercooler is bit illusive.

Here is a intercooler diagram to help locate .

[jimmy57]

If the trans was never felt to engage and if the engine speed picked up to even 1200 rpm and it didn't make any effort to creep then the intercooler blockage can be ruled out. If it is definitely felt to go into gear and engine revs up and straining of engine is felt then look for things like parking brakes shoes frozen to drum and even brake pads can freeze to rotors if you splashed through a puddle just before stopping.
If the trans is never felt to engage an the engine revs freely just like it was in Park then the rubber seals for clutch drum(s) with wear and age have hardened and the cold has caused some further shrinkage and it is losing clutch apply fluid. The first thing to do in this case it let it idle for 30 or more minutes so the conducted heat of engine warms up the transmission to see if that doesn't restore function. IF not before giving up get Lucas or other brand transmission additive that specifically addresses seal issues. The additive will mention containing additive for seal conditioning. Since the transmission had good function before the cold weather and period of no use it is unlikely it is a catastrophic failure.