I drove a 2007.5 6.7 today. It was a 3500 4x4 dually. My question is whether or not the final drive is still really bad for unloaded hwy driving. Didn't it used to be .79 or something like that. Seems like I read a discussion on here saying that it was changed to .74???

 

I think a little high but about 2200 rpm at 70mph. A buddy just put 35's on his and only got approx 100rpm lower with the bigger tire.

 

Anybody else know what it is?

 

Check out this previous thread.
https://www.dieseltruckresource.com/...d.php?t=151253