My story...
3 weeks after I had the transmission cooler installed, the hose going to the cooler came off the connector. With a pool of red on the ground, it looked like the car was bleeding to death. Caught it real early, probably lost less than 1 litre before I pulled over, when it decided to dump all of it out. Had the car towed, topped it up, and all was fine.
14 months later, the hose on the other side of the same connector fell off... This time, I didn't catch it until the car barely moved even at 4000RPM. Fluid was low enough that the car at that point would not move at all, forward or reverse. Had the car towed, flushed tranny, topped up fluid, and again, all was fine.
Spot the loose hose, top it up, you may be out the door for less than $100 even with synthetic fluid. Consider it a tranny flush.
Your mileage may vary...
VK