I would be very careful on going past the oil drain on just the cj4 oil it has half of the TBN needed for engine wear. How ever Amsoil has been doing some RD on the the TBN's and has added some back to be able to go longer I posted this info
here.
New AMSOIL Premium API CJ-4 Synthetic 5W-40 & 15W-40 Diesel Oils
AMSOIL upgraded the technology on DEO, increased the TBN to 10.4 and created a compelling extended oil drain capability of up to three times (3X) original equipment manufacturer’s (OEM) recommendations. The extended drain interval on the reformulated DEO is now defined using both miles and hours for a wide variety of on‐road and off‐road applications. Upgraded
AMSOIL Premium API CJ‐4 Synthetic 5W‐40 Diesel Oil also has a documented fuel efficiency benefit of up to 3% over conventional 15W‐40 diesel oils. With the upgraded technology,
AMSOIL DEO can also be recommended for a longer list of worldwide specifications.
How did we do this?
Answer: AME is an outstanding product for wear protection and was the standard used to build the new Premium API CJ‐4 Synthetic 15W‐40 Diesel Oil (DME).
AMSOIL Premium 15W‐40 Diesel Oil is formulated to resist breakdown from continuous operation and high loads. Built with heavy duty detergent/dispersant additives, this high TBN (10.4) formula is naturally resistant to the detrimental effects of high soot loading. It keeps soot particles suspended independently, preventing them from attaching together to form larger, wear causing particles.
AMSOIL Premium 15W‐40 resists heat and breakdown better than conventional petroleum oils for long lasting performance and protection.
So how does this affect the new diesels.
Answer: You can go ‘3X OEM’ refers to the extended drain interval definition of
AMSOIL 5W‐40/15W‐40 diesel oils. ‘3X OEM’ means
AMSOIL diesel oils extend drain intervals up to three times (3X) the original equipment manufacturer’s (OEM) recommendation as stated in the owner’s manual or other supporting technical documents. For example, the OEM drain interval recommendation is 15,000 miles for a Volvo with an ISX engine under severe service, thus
AMSOIL CJ‐4 Diesel Oils will extend the drain interval to 45,000 miles. Likewise, a Kubota M8200 Series Tractor has an OEM drain interval recommendation of 200 hours;
AMSOIL CJ‐4 diesel oils extend this drain interval to 600 hours.
AMSOIL drain interval cap ‘Not to exceed 50,000 miles/600 hours or one year, whichever comes first’
This is to be understood using our Oil Filter as it filters better.
I have included the complete info attached.
Bill