If your asking about the 6.4 tranny pan, it has a better internal filter than the 6.0 and is slightly deeper so it will hold more fluid. I think that’s the main difference, but I could be wrong, it’s been known to happen. I upgraded mine because I was changing the fluid anyway it didn’t cost that much to change it out. But, cost is relative.I know this is a popular upgrade for the tranny on a 6.0, but I don't know why.
Can you educate me?