Help! Auto Trans Winding Up- Not shifting gears

Hello, I have a 1996 Dodge Avenger with 60000 on it and just today it began winding up in drive, and not shifting to the next appropriate gear for the speed. I stopped and checked the transmission fluid, it was ok level wise but the high rpms had it kind of bubbly. I checked the oil level which was a quart and a 1/4 low. I added more oil, and the car seemed fine, but a few miles later the symptom returned. I stopped the car for about five, levels were fine, and it behaved properly after restarting til I had to sit through the Burger King drive-through, and then started revving without shifting from the first gear again. The car isn`t running any warmer than normal, and I can`t see any obvious signs of disrepair.This transmission is only about 19000 miles old, and I last changed the oil 3,000 miles ago. On such a new car I shouldn`t have had to add oil, but I don`t know. Someone help me figure out what may be the problem, or what the possible solution may be. Email me and reply to the group, as I check my email often. Thanks, Jeff.

You mention the trans only has 19K on it. Are you saying this is a replacement trans, or the car has 19K on it as well? No matter. This is the A604 trans and it has no bands, or governor. Its electronic (basically computer controlled) and operates from feedback fed to it from various sensors. First off get it to a garage that has a scanner that will pull DTCs (diagnostic trouble codes) from the computer memory. That will give a clearer picture of what is going on. Hopefully it is a sensor or controller going out rather than an internal hydraulic failure.
Respectifully submitted, Loren Knighton Knighton Automotive Woodland, CA. under the hood since ` 64

extended warranty, redone by dealership). So, yeah, I guess I`ll have to take it to the dealer again. Any idea of what a dealer performed warranty repair would carry in terms of the replaced item`s individual warranty? My warranty ceased from the bumper to bumper persective at 50k. I suspect that the redone transmission should have it`s own warranty? Otherwise, they could`ve pretty much done a let`s just make it last past 50k type job. Any ideas? Thanks, Jeff.