What's the deal with oil in any diesel getting so dirty so quickly? Mine is dirty within a few miles of an oil change. This is true for all diesels, so I assume it's normal and not indicative of viscosity breakdown, etc.
I know that the Army hardly ever changes the oil in their humvees (seen it done ONCE in my seven years of service). When they do, it's only after an OK from an oil analysis lab.
I haven't got the money do spend $45 to $50 beans every 6k for an oil change, so I use Rotilla. They now have a synthetic version, but I know nothing about it.
Many people experience more severe oil seepage (more than normal) with a high mileage diesel (like the 123) when switching over to a synthetic. Another reason for me not to risk it.
Synthetic oils are definitely better, but I figure thousands of truckers use Rotilla and get half a million miles out of those engines easily, so what the heck.