GEEZ! I never knew how much there was to know about diesel engines. After I bought my '02 GMC 2500HD Duramax, I found this forum specifically for Duramax. www.dieselplace.com.  All this stuff about 'low sulfur diesel' and the now 'Ultra low sulfur fuel' and all the controversy about needed special additives for fuel lubricity with the 'ultra low sulfur fuel' not to mention "what's the best fuel filter, oil filter, oil viscosity, transmission filter and oil" just to mention a few topics, is mind boggling! Everyone has a different opinion. Been reading for days. So many topics. Finally about narrowed down most of it to the 'best and necessary'.  Not cheap for the good stuff, but is it ever?

understand completely. nothing is ever easy anymore. was having trouble with the 90 and posted a question at another site and got so many conflicting answers it was mindboggling. only problem was that all the answers made sense.

a lot of the choices are your own personnal preferences and you just have to try and make the best judgement of the facts as you can.

Your 02 diesel can still legally use Low Sulfur Diesel. The factory set up should run it fine. Starting in 2010, only Ultra low sulphur diesel will be available for over the road use. All diesel over the road vehicles 2007 or newer have the ULSD components installed at the factory. Running the ULSD in older than 2007 vehicles can and probably will dislodge deposits internal the engine and clog fuel filters. We are already experiencing this in our city fleet. After changing filters numerous times  the problems seems to clear up.
As the city fleet moves toward B5, B20, and other biodiesels we will certainly have more problems that have not yet been discovered.  I am however one hundred percent behind alternative fuels that will reduce our dependency on foreign oil.

Scott

 Trouble is, I can't find LSD anywhere. It's all ULSD. Anyway, I just ordered a bottle of Opti-Lube Summer Blend. It was one of the best additives in an independent study. I see how that goes.