last tuesday i was driivng down the highway when my car stated to slow down and made a low pitch rumbling sound, when i opened the hood, i saw a little smoke, the coolant tank was bubbling, and i saw coolant pouring on the ground. i towed it to my house and looked at it and in the coolant tank it was darrk colored coolant. i disconnected it from the radiator and drained it out. at the bottom was a binch of sediment so i shop vaced it out. when i looked in the radiators fluid was bright and clean looking before all the draining i did. i also changed out the therrmastat and the belt cuase it looked rough. i checked the oil and it looked like it was just oil and was full enough and i checked the transmission fluid and it was fine too, i thought it would be good to go so i drove about 8 miles to my dads. when i was driving back, it made the noise againso i backed off then it stopped and i made the rest of the way (which wasnt long) to my house, the temp was only at like halfway. when i got to the driveway, i went to repark so i backed up and iwhen i wasw going it just stopped moving. i opened the door and there was a very large puddle of transmission fluid (red) all over the ground. what wrong with my car?