Its what is already in it lol. I was very impressed with the transmission fluid and how it made it feel. I am with you dont fix something that isn't broke. I just can get redline at summit for about the same price as Castrol. It always worries me as its gone 80k with no more tick using Castrol edge.If it isn't broke, don't fix it. Why use a 10 dollar a quart oil if you don't have too? With the results at ram forum you can even get an oil soluble molybdenum additive that will give you some insurance against hemi tick without the cost, lubegard biotech = poor mans redline.