Can of worms opened!!!:hehe:
I was using Amsoil, but plan to switch to Shell Rotella T 5W40 synthetic diesel oil simply due to economics. I can buy it locally, no shipping or membership.
Others will chime in with their preferences. Really, most oils are quality today, some just need changed sooner than others.
I like the john deere oil, it still is the CI-4 so it has plenty of zinc and phosphorus so you don't have to run additives like the cam manufacturers recommend with CJ oil. You can get it for around $13 a gallon.
Youre asking a broad question & requesting a specific answer. What oil to run depends on many things, such as the climate & conditions you live as well as the mods & uses of your truck. If this specific info is what you seek you need to give more details about your locale & truck. You really want to know what to run then do some oil analysis on different oils in your truck. Otherwise its all a matter of opinion. All name brand oils are basically equal. Run whats on sale & change it regularly.
I used Rotella synthetic 5w40 once and did not like it and why I tried out and I'm still using Amsoil 5w30 HDD. Heck even some of the farmer in my area no long use Rotella as they say the CJ-4 oil does not hold up as well in there farm equipment like the CI-4+ oil did and have now switched over to John Deere oil being its still CI-4.
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