i got a 91 D Ram50 with 240k miles, I was driving threw Sacramento Ca a couple weeks ago and i noticed my truck was running a little hot so I pulled off and let it cool down. about 20-30 mintes later i hopped back on the freeway and got about 10 miles father down the freeway right into the middle of downtown sacramento and my truck started being kinda goofy feeling. it was about 100 degrees out that day so i thought it was running hot again the temp gauge was just about half way. W was driving with the windows down and while passing a semi truck i heard a lud flapping noise kind of like a piece of paper in a fan. i thought it was the semi. so i kept going just to get passed him and realized the noise didnt go away then my truck started to lose all power so i downshifted to 4th gear and still no power. then to 3rd still no power but the truck was still revving at high rpms so the motor was still kinda alive. When i looked in my passenger mirror to get over to stop all i could see behind me was a WHITE SMOKED OUT freeway!! all that white smoke came from my poor little truck. when i came to a stop the truck was dead. i tried to turn it over and all it did was like free spin. almost like there is no compression but im not sure. just brought the truck to my high school auto class and looking to tear it down tomorrow. Any advice on where to even start looking for problems would be a big help. Please help my little Ram50 get back on the road ASAP!