I plan on changing my own oil on my 2005 with 5.9 next week. What is the best oil to use. 15w40 or 5w40 and how many Gals do I need to buy.

I'am also changing the front and rear diff oil will 75w90 work just fine?

 

I'm not going to touch the "Best" oil but I use Valvoline Premium Blue which is also reccommended by cummins. It is the 15w40 and I go 6 to 7,000 miles between changes. I also use a fleetguard stratapore filter. You will need 3 gallons.


Yes 75w90 is fine.If you do a lot of towing or heavy towing I would go 75w140 oil.

 

amsoil,redline and mobil 1-if you ask me. i get amsoil delivered to my house cheaper than i can buy mobil 1 in the stores. redline is the most expensive.

 

I use 15w40 and 85w140 cuz I'm in the desert. IMO, 75w90 is only good for towing light. Craig

 

Agreed, after trying and trying to scrounge up more CI4+ oil, I gave up! Been running Premium blue and will continue to do so! 75/140 in the rear for me since I tow heavy... Might consider the 75/110 from Amsoil this next change. Kind of a nice inbetween!

 

I run valvoline premium blue as well. Look into a by-pass oil filter for your truck, amsoil and FS-2500 are great places to start looking.

 

I thought the premium blue had also changed to the CJ standard now? Where does everyone get the premium blue? For the last two or three changes I have been running the rotella syn 5w40 first for winter, then cause it is still CI-4 plus.

 

You should look at and get a demo on the Schaeffers oils and lubes.
Very impressive.

 

YOu are correct Premium Blue is now CJ, however I am getting GREAT UOA's with it . Granted I only do 5,000 mile changes but this oil and that distance are doing just fine. I know others who use this oil 7-10,000 with absolutely NO PROBLEMS> No bypass either. There is a "Premium blue classic" you can get in 5 gallon buckets. This is the good old stuff, I cannot get it in CA.

 

X2.....Schaeffers !

I run Supreme 7000, (synthetic blend)

 

X3 on Schaeffer 7000. I was leary of a semi-syn but I just got a great UOA and TBN stayed up like nothing else I've used - 11.61 at 9500 miles! I've had the best UOAs with 85w140 in the diff. Craig

 

Just use Amsiol. They don't call it the first in synthetics for nothing. Check thier site for comparisons.

 

Well oil threads tend to get pretty good. I guess biggest debate for you is how often do you plan to change your oil? If you change it every 5K miles then the synthetics are probably not for you. To help offset the cost of the synthetic oil, you should extend your drain intervals... For your rear differential, any GL-5 rated synthetic should suffice. The 75W90 is the proper weight per the "book," but you can see some guys are running heavier weight. The diffs should not require a friction modifier, but some guys running the heavier oils or even standard weight have needed it to stop the clunking in the rear on tight turns...

 

I'm a Delo 400 fan...had pretty good success with it. I like Schaeffer's as well. One brand that did well for me also was 76 Royal Triton 15W40...great cold cranking numbers and good wear numbers as well. Decent price too.

 

ive been running Delvac since day one