no, but i need to... i really don't have the $$$ to pay someone else to do it, and I want it done right... i'm researching it, and am going to probably do it myself. i am running 35'' BFG AT's, so they're not putting as much stress on my trans. as for example, a heavy 35'' mud terrain. i'm going w/ either 4.10's or 4.56's. 4.88's and my foot = <10mpg.

it probably wouldn't be that bad, but this truck is staying my DD, and I am not going to upgrade to the 37-38's.
in the end, i will probably go w/ the 4.10's. the ratio will net me a realized 3.73 ratio, and i will be back in the stock powerband. i need to preserve my mileage as much as possible, as i already noted. i also have the 5.4, and some good power upgrades, so I don't feel I need to go as low as 4.56 or 4.88.