Sorry! For the confusion on the last post...I had my number wrong it should be...Anyone have the 4.3 axel? Gas mileage?

I am looking at purchasing a F350 SC DRW 4X4 with a 4.3 axel (Tow Boss package). Does anyone have any experience with this axel? What would be the difference in gas mileage with the 4.1vs 4.3? I would like to have the higher towing capacity (pulling a 5th wheel) but, I am looking at doing a lot of traveling and I concerned with the gas mileage. Thanks!

Towing or Fuel Economy. One or the other when it comes down to it. If what you are towing warrants that tall a ratio to stay within weight, then you need to think more in line of "safety vs. fuel economy", else, stick with what you know and tow smaller loads.

The price point on heavy towing is durability and relative cost of maintenance. Better fuel economy can be measured in tenths of a mile, not in double digit improvements between one tow vehicle over another.

Case in point. 8,100 lbs. loaded Fifth-Wheel with an Chevy 5.0L Gas, 5-Speed, and 4.30 rear = 9-10 Mpg. GMC 6.0L Vortec, Auto and 3.73 rear = 10 Mpg. 7.4L Vortec, Auto and 4.10 rear = 8-10 Mpg. Although there was a great difference in non-towing fuel economy, it all seemed to come down to an average of 10 Mpg with the same trailer and three different gassers.

With the 6.6L Dm/ZF-6 and 4.44 Rear (19.5" wheels) = 12 Mpg. towing same trailer.

Consider the point at which you trade off fuel economy for capacity, and you will find that the rate of diminishing return is either safety or frequent replacements of costly parts. Hope that helps.