This is a comment rather than a question based on real world experience.

I was told by two Nissan dealerships that the transmission in a 2019 Nissan Titan XD with Cummins engine was a heavy duty unit that had very hard and abrupt gear changes. They recommened fluid and filter change with Nissan Matic K ATF at 20k intervals but expected no shift quality improvement.

Well, I dropped the pan, replaced the filter with Nissan OEM but refilled with Amsoil Signature Multi-Vehicle 100% Synthetic ATF (ATFPK). It appears this fluid made a significant improvement to the shift quality. Now shifts are firm but no more slamming into gear.

The removed filter was not excessively dirty and the pan had minor collection at the magnets. Pretty typical.

From all observation, the Amsoil fluid works wonderfully in this application. I've seen online success videos, but was a sceptic. I have no commercial interest in Amsoil but this honestly was a fantastic result.

For what it is worth.

Best regards,

• MMG