That time for our 05 3500 to get its fluids change. Since I'm the second owner and not sure what the previous owner ran in it. Would it be wise to change everything and flush the fluids?

What do you all run in your cummins for oil?

also, someone said to drop in some 2 stroke oil in the fuel every time I fill the tank. Reason to do so or useless. What do you add for fuel additives. If anything.

 

Also should note that it's a daily driver, will tow probably a few times a year and it hauls a good amount of stuff. It's running strong at 92k miles.

 

2so will help keep things lubricated. run ashless (tcw3) 2so. i add it to my truck every 3rd tank or so, not every fill up. i will also add dexron atf every now and then to clean out the fuel system. guys run all different kinds of oil, i know rotella is a common oil that guys use. i use mobil delvac oil. i dont care to use rotella because it puts off a stronger oil smell then any other oil, from what i have read. you didnt say what you have for a tranny but if its the g56, mercedes (who makes the g56) says to use mobil delvac synthetic transmission fluid 50 and most guys over fill by 1qt. the truck manual says to use some atf or something, but dont use that. if you have an auto or the nv5600 then i dont know what to use. if you have a manual but dont know which one it is because half way through 05 they switched to the g56, g56 reverse is too the left and down, nv5600 reverse is to the right.

 

I knew I was missing something! It's a auto, so a 48re correct? I ordered a oil analysis last week so that'll tell me the most.

I've heard so many mixed reviews if puting oil and atf in the fuel. I know some who don't but then some who live by it.

 

One ounce per gallon on the 2 stroke oil NEVER RUN ATF! It's a cleaner and will ruin your injectors AND CP3!
Auto 48RE uses ATF+4 any seller even Walmart uses the same mix for their ATF+4 It all comes from the same producer and bottled under a dozen different names!
Any diesel motor oil will work it ALL turns black so 5k is the most I ever run between oil Changes.
11BC was right on about the G56!

 

me and a lot of other guys will disagree with you on that. it has helped a number of guys that were having issue and one guy i know has almost 300,000 miles on stock injectors. he ran atf when was having issues and it cleared it up. has ran great for tens of thousands of miles since.
OP, i also for to mention greasing the areas that need to be greased.