Transmission or something else?

My son is a conservative, teenage driver who owns a 2002 dodge neon; front wheel drive and automatic transmission with 100,000 miles. When driving home last nite, he got about 200 yards from our home when the car began to coast. His transmission, or something, no longer engaged the drive wheels. He parked the car and informed us that he has no forward gears or park; but does have reverse. There is no indication of leaks, nor was there any mechanical indication of something wrong until this “all of a sudden” event. What do you think could have happened? If it’s an expensive repair, we will probably not perform it, but if there is hope that it might not be, I would pay a transmission service to analyze the condition and keep my fingers crossed.

Has anyone checked the level and condition of the transmission fluid? The very first thing I would suspect - since it was an “all of a sudden” event - is something like a blown transmission cooler line or other catastrophic fluid loss. Basically this sounds like the transmission suddenly lost all/most of its fluid. So check the transmission fluid first - look for obvious signs of leak under hood & car, on driveway and road.