My brother ordered a '99 F-350 4x4 DFW with the 4.10s and the 7.3 with automatic and it never got more than 11 or 12 mpg. Ran great but it burned a lot of diesel, I tried to get him to get 3.73s because he really didn't pull much. My Ram 3500 diesel I have now has 3.42s! Hardley ever gets much past 1800 rpms and still pulls better than anything I've ever owned.When I was prepping to order my 2001 f350, I was wanting the 4.11 gears, but in a single wheel f350 with the 7.3 diesel, only the 3.73 was available!
It was not long after having it I was glad it had the 3.73!
Now if it only had a 9 speed manual instead of the 6.....
It could use one more intermediate gear (cant remember between which ones) and 2 more overdrive gears!
If I had been able to get my way and got the 4.11, it woulda just been more wasted fuel and more engine wear!