Taking the Plunge (Gear Swap)

I tow with a 2 valve V-10 In an '05 Excursion that had 3.73 gears, I swapped up to 4.88 gears and 35" tires (from the stock 31.6" tires). At the time we were towing a 31' 9500lb toyhauler and seeing 6 to 7 MPG on trips up/down the East coast with the stock 3.73 gears. After the gear/tire change which gives an effective 4.39 ratio, we saw 9 MPG with the same load over the same route at the same speeds. Where the stock setup would downshift out of OD if we ran over a shadow the new ratio didn't drop out of OD a single time on the highway between Savannah and Philly. It was like a new truck, so much better! With your more modern engine and much better transmission I think you will be a very happy camper with the new deeper gears.