Why I add 12% (one gallon) of gear lube at every oil change...

[Waterloo]

(08-11-2017 )RStewart Wrote:  This is great info. I also read the thread about the oil bypass. I was interested in the bypass & extended drain intervals. After reading these two threads I've decided to go ahead with the bypass but keep my regular interval. I have a 2011 Freightliner Cascadia with a DD15 in it. Manufacturers recommends 10w30 oil changed every 50k miles. I've been running 10w30 Delo 400 synthetic blend & I change it every 30k miles. I also thought oil sampling was a great tool but now I'm thinking just sampling for info but changing the oil every 15k-20k miles.

I'm really interested in what weight of oil you use & what gear oil you add. This really makes sense to me.

I run a 2008 ISX, and if I had your motor, I would be running regular Rotella dino in it, don't waste your money on synthetic. As far as gear oil, Rawze did a write up on this regarding the newer SCR motors and recommended a GL-5 lube over the GL-4 many of us are running in our none SCR motors. I would also recommend oil change intervals of 15,000 miles along with a good oil by pass system if you keep the mandate. No oil bypass, I would be changing oil every 12,000 miles. That soot will eat your motor alive, synthetic or not.