Hey Adam...

It might be something stupid like a loose trans cooler line -- actually, that's likely a problem. I'm not sure if you know about this, but to check the fluid level on the 4hp, the car has to be warm and running. After pouring a quart/liter/whatever in the pan, the stick will read as having some fluid simply because the pump hasn't picked it up yet.

I would call the shop, tell them what happened and have them tow it in. A $1600 rebuild should buy that luxury, no questions asked.

best, whit