My friend (2000 GT w/ T45) and I were heading down to Austin for the day, and as we were passing through Round Rock, I see him drop way back. He calls me up and is like, "exit, exit now!" So I cut several people off (I'm in the far left left lane) and get off the highway and pull into a Pancho's parking lot. I call him back, and he tells me his tranny popped out of gear and won't go back in. So I circle around and pull in front of him on the shoulder. He can't go anywhere, so we go back to the parking lot and park, we go back to his car and push it about an 1/8 mile up the shoulder, and make it halfway up the exit ramp. But it's kind of uphill so we can't get it the rest of the way. So we go back, get my car and a tow strap from some city workers that were nearby and go back and I tow his car into a parking lot on the access road. He couldn't get his tranny into any gear except for 4th. He's been having problems with it lately and the Ford dealership are being ******* about fixing it for him even though it is under warranty. What would cause his tranny to go out?