Ford Expedition Weird Transmission problem

RR99

This is a 2003 Ford Expedition XLT 4WD 4.6L Triton .. First there's no lights on and no codes.. Setting in the yard it goes in all the gears fine without any delay including 4hi and 4low (forward & Reverse), Pull onto the highway and pulls strong through 1st & 2nd gear no problem then it feels like the brakes come on by their self and the more gas i give the harder the brakes feel.. If I let up on the gas the braking stops and starts again if I apply more gas.. I feel like it my be a sensor but im puzzled.. Ant help would be appreciated.