2003 Taurus SEL 3.0L DOHC Trasmission Trouble

To start, this is probably unrelated. My A/C started acting funny the day before the problem. The air would blow super ice cold at idle and up to about 40 mph then go warm and humid like the air outside. I cahnged the drive belt and the tensioner because the tensioner was loose.

Now to the real problem. I was driving around 75 mph and went to pass a car to get over for the off ramp. The car started to go into overdrive and then there felt like a small power drain, not quite a jerk, but a little like a jerk and then engine power came back for a few seconds and then it seemed as though the transmission wouldn't engage. I pulled over and cracked the hood and there was a weird smell, not overpowering but faint, kind of like oil burning on the head from spilling after filling, but a little different too. When I put th car in gear you can feel a pressure change and a little rock, but when you hit the gas it only revs free. This is true for R, D, 1 and 2. Any help would be great. Is it the torque converter?