I have 27,000 miles on my 6.7 cummins and I went ahead and filled up with red diesel the other day. I live near Houston and with the hurricane driving up fuel prices and the tank at work being offered to me it was hard to refuse. So I filled up on red diesel and have had no issue after three tanks of it. The diesel is ULSD just red since it isnt taxed. I think it doesnt matter if your diesel is red, green, clear, gold, or blue, if its ULSD, it should burn.  

actually red fuel has different salfur(<--prolly spelled wrong) count. so its not the ulsd  

Red diesel isn't ulsd.It's used for tractors.and ist's illeagle for use in diesel vehicles on the road.Because right know it's most likely screwing up your injection pump and fuel system.  

its def ulsd, i checked through everyone all the way back. it's just red. my company had until 2010 to be running red ulsd but chose to start now anyway as a way to say they are helping.  

My bad.I wasn't aware of that.  

there are both types of Offroad diesel... and it's technically illegal to run in your personal diesel vehicle... if you have a company vehicle then you can get away with it as long as you're paying the tax on it through a corporate account... and it can get you severely fined...  

it's off road diesel. they don't tax it the red is dye.all DOT has to do is look at your fuel fillter. and I know that if you run it in florida and DOT gets you. it can be like a $5000 fine!!!!!!!!!  

In Ohio, it's supposedly $100.00 per gallon fine if they find red fuel in your tank. Problem is, that dye sticks around forever, even through several tanks of DOT approved stuff. You can fail a dip test and get fined even though you have taxed fuel in your tank and have been using it for 2-3 tankfulls. Just that one fill-up of red fuel can be very expensive in the end!  

red fuel is not ulsd, whoever you checked with is wrong cause the sulfur count is is alot higher.  

Maybe the stuff you got from work was ulsd, but nothing around here is. The Red fuel is for tractors and equipment, and i dont know if its cause there is more sulfur, or if its the dye but the red fuel will make your truck smoke a little more. If you fail the test, not only do you have to pay the $100 a gallon, but the siphon every last drop out of your tank, and leave you on the side of the road. Apparently they arent required by law to let you get to a gas station first. I know a guy whose dad got caught with a full tank of red fuel and red fuel in his auxilary tank, and the dot drained it all into some portable tank, fined him, and left him on the side of the road. I ran red in my 99 once. I had been hauling hay for my fiancee's dad, and when i got back to the farm i realized i was on E, i probably didnt have another 2 miles worth of fuel, so i was gonna put just enough red fuel into my tank to get me to the gas station, but i wasnt paying attention and by the time i stopped pumping i had put over 3/4 of a tank in my truck. Whoops, just glad i didnt get caught!  

#2 red fuel has higher sulfur and isnt taxed hence why its off road only.  

I can honestly say I've never heard of ULSD red fuel. Red fuel is not taxed and "for off-road use only", but I suppose there very well could be red ULSD as new trucks used for things like forest service or construction or oil field service that never see a public road are still sold with all the new emissions crap bolted to them. To run "standard" red fuel at 5000ppm sulfur would poison a new truck quick. I hope for your (and your truck's) sake that red fuel you are running is ULSD because along with the hefty fines the man will give you if you're caught with it, it will also void your engine and emissions system warranty if you have any trouble there. A new CP3 and injectors for that 6.7L will likely cost you around $7000.00 to replace if something goes south. The DPF alone is said to be a couple grand to replace and you WILL plug it up (and the EGR system) running anything but ULSD. Good luck!  

is your truck still running ok? i have been wanting to run red fuel in my 6.7 too.  

You'd better take the DPF off if you're going to run red diesel. Otherwise, you're in for a world of trouble.  

mvaughnjr:
I have 27,000 miles on my 6.7 cummins and I went ahead and filled up with red diesel the other day. I live near Houston and with the hurricane driving up fuel prices and the tank at work being offered to me it was hard to refuse. So I filled up on red diesel and have had no issue after three tanks of it. The diesel is ULSD just red since it isnt taxed. I think it doesnt matter if your diesel is red, green, clear, gold, or blue, if its ULSD, it should burn.

I wont claim to be an expert on this subject, but I can give you some facts.  There are basically 3 types of fuel that are petroleum based for sale in the U.S.  #2 Fuel oil, or diesel, comes in the ultra low sulfer, low sulfer, and high sulfer.  The high sulfer is always dyed red, and is very rarely used anymore.  It is more expensive than the others. Both the others can be dyed red at the pipeline terminals.  This is done to identify if it is taxable or not.  The only difference is the sulfer content between them.  The low sulfer is almost entirely phased out in the US due to EPA restrictions for all diesel applications.  Most states have stiff penalties for using non-taxed fuel in any on road vehicle.  Refridgerated semi-trailers are one of the only exeptions.  Of course, there is #1 fuel oil, AKA Kerosene.  This is used as heating oil and also to blend with #2 in colder climates to prevent fuel gelling.  It can be dyed red as well.  
In Illinois, the law is as follows:  Having dyed diesel in the fuel tanks attached to a licensed motor vehicle:
First Offense: $2,500 fine, Class A misdemeanor
Second or Subsequent Offense: $5,000 Class 4 felony
So as you can see, you may or may not want anyone to know.  But I can tell you from experience, the dyed fuel is fine as long as it is the ULSD. I ran dyed fuel in my '04 QC for 70,000+ miles with no issues, while it was readily available to me.  I would do the same with my '09 Mega-Cab if it was available for me now.