well, it sounded like there might have been a bolt or something rattling somwhere in the engine. when i heard it i pulled over and lifted the hood to see where it was coming from. It was a noise that was consistent with the RPM's because when I slowed down to pull over it slowed down. I was close to a small town so I decided to go ahead and make it to the town, find a gas station and figure out my next move. As i neared the gas station, it was struggling to run (like it was bogging down) and died. I let it sit for about 3 hours while a friend came with a trailer and when I tried to start it to hopefully pull it on the trailer, the starter would make a loud click (only one as if it engaged the teeth on the flexplate) and then a high pitched electrical noise (like the solenoid was trying it's damnest to turn the engine) until I turned the key off. So, the block would not turn over at all. I checked under the truck and there were no puddles of oil. I checked the oil, and there was no water in it but it smelled burned and was pretty black considering I had the oil changed two weeks ago. So I am afraid that the engine is seized. I will go out later today and see if I can get the crank to turn when I get a few free minutes.