My new dodge diesel quad cab long bed 4x4 with an outomatic transmission has a slight knocking or pinging sound at low rpms between 1500 and 2000. My truck only has 220 miles on it and my friend told me that it is just normal diesel break in noise. It sounds like the noise that a gas engine makes when you put bad gas in it.

Can anyone give me some insight into this issue?

 

At next fill up put some Stanadyne Fuel Additive in it and see if it goes away. The dealer may have put bad load of fuel in it...

 

Pinging is related to the multiple injection events on the 600 and 610s. Fuel additives may reduce it. My 2005 and all the others I drove had it. Cummins is reported to say it's normal for the beast.