Trouble with 2004

[Sevarg]

Has anyone experienced this, what may be the problem? While driving along in 6th gear at 70mph, a loud rattling noise began. The noise sounded like a coffee can containing nuts and bolts was being vigorously shaken. At the same time blue/grey smoke was billowing from the exhaust pipe. The smoke was thick enough that my vision was obscured, upon stopping and as the cloud reached the truck. The vehicle is a 2004, 2500, Laramie, with manual transmission, 4X4, towing package, quad cab, short bed. The malady occurred when the odometer showed 1,027 miles. The engine oil level was between the high and low marks on the dip stick. Currently the vehicle is at the dealership and the problem is being diagnosed. All I know is the Dodge/Chrysler towing package works well.

Thanks in advance
Sevarg