Slipping Transmission

Recently got 06 Titan. A few weeks in the transmission seemed to be slipping in fourth gear. Today when I pulled out of my neighborhood I had barely any forward drive. The engine would rev but the transmission was slipping really bad in all gears and very jumpy. I quickly turned around and barely coasted into my driveway. It seemed to have basically no forward bite. I checked the trans fluid and it seemed to be at the correct level and didn't smell burned. Any ideas?