Front and rear gears
I have a 2000 F250 7.3L mostly stock engine. I have about 142,000 miles on it but I think it is lacking some power. I installed a big AFE air filter, installed a 4" exhaust and Superchips tuner (I am not impressed with this tuner.) I usually pull a 30' Fifth wheel and it does ok, but when I hit hills, I will be at a crawl. I have had some heavy loads on this truck and each time I make to the top of the hill but it is slow. I am planning some upgrades with a TS chip, but I thought maybe I should change out the gears. Is it possible to go from 3.73 gears to a 3.90 gear instead of the 4.10 or 4.11 gears? I figure with the 3.90 gears, I would get some added pulling power but not completely lose my mileage. I am averaging 17.0 and that is town and highway miles combined. In town will be around 14.5 and the highway cruising around 62 mph I will get 19.5.