redline shockproof
Depends upon how you drive.
There is a lightweigh shockproof, a 75w140 synth. If you want better fuel mileage.
Superlightweight is the consistency of trans oil. rated at 75w90 i believe. probably too light for anything we would do.
If you have ever used shockproof, it is odd. it is grey in color. MIGHT EXPOSE YOU TO WARRANTY QUESTIONS YOU DON'T WANT. I use in in my trail rig and my son's jeep.
Absoultely nothing wrong and lot's of benifits to running a synthetic motor oil in the Cummins. Just make sure it is diesel rated and a good wieght for the ambient temps. Amsoil Marine diesel looks awfully good.
If you get an oil analysis kit ($30 at genos) you may be able to go with extended drain intervals, thus justifying the addition price and protection. BUT ONLY POST WARRANTY