Often times when a cooler line blows off and you are unaware of this it is too late by the time you find out what happened and fix the line and refill the trans as the damage is already done. You would have lost more than a gallon of fluid if it quit moving when this happened and that is likely why it isnt working properly. I would definately start by checking the fluid level and make sure it is full. It is a gamble but sometimes works out ok as the fluid leaks out pretty fast if a line blew off and due to low pressure it wouldnt move and hurt anything, but the momement before it is going to be hard on the frictions. Its not going to hurt anything to top off the fluid and see how it works, if not ohh well you are out a few $$ for fluid but at least you know and may make another race or two.
