Okay, this morning, on the way to work, the truck started to shake like it had a flat tire. We pulled over, but didn't kill the engine, just got out to check tires. No flat. So we looked under the truck to see if anything was hung. Nothing. Truck wasn't shaking while idle. However, once we put into drive, it began to shake again. We found a place to pull over and park off of the hwy. Killed the engine. Looked to see if anything was leaking, nothing. We then tried to crank the truck. Nothing. Wouldn't even turn over. All we hear is a hissing sound. The sound seems low and on the driver side.

Any ideas? We thought maybe U joint or drive shaft but wasn't sure if either of those would cause the truck not to start. This is our only form of transportation right now so we hope it is something that can easily be fixed.

Thanks!!

Post the year and engine size as this needed to answer your question.