So while I'm sitting on the side of the highway waiting for aid, I thought I'd see just how bad this is going to hurt my wallet.

The line running from the transmission to my inline filter popped off and dumped all of my transmission fluid on the highway at 75 mph. Transmission started acting weird so I pulled over. Provably about a quart left when I turned off the truck. How much damage can I expect?

 

If the transmission wasn't under a big torque load you might be pretty okay. What specifically was weird about the way it was acting? That might provide some clues.

 

only way to find out is to fill it up and go for a drive.

 

Popped out of OD. Start Revving higher. I repaired the hose and refilled with fluid. (on the side of the highway in the dark which was fun with people wizzing by at 80-90 mph...yikes). No problems getting home and temp never exceeded normal. So might be OK. I'm having a new line made without the splice I have in it, dropping the pan to check for debris, replacing both filters and replenishing fluid. Also have to wash the old girl. Transmission fluid is all over her now. A nice red sheen. :-)

 

Here's hoping you're good to go then; sounds like you will be. I'd assume the hydraulic system would have started to have issues before you ran into a lot of heat issues. Loss of pressure is likely why you popped out of OD/revving.

 

You might just be okay, but with some miles peeled off of the end of the transmission's lifespan. Your plan sounds like a good one.