I recently was driving down the freeway when my car rpms shot up and MIL came on. Checked it and the input speed sensor was bad. Or so it says. I tore the trans pan off and replaced input and output sensor on the car. Gasket seemed to be in good shape still so reused(probably not the best idea). Got it all back together (new coolant and trans fluid) and not it goes into gear really hard. And I hear a hissing coming from underneath the car. And the d symbol flashes when i put into drive. Anyone know what could be going on?