im not running 33s but i do have 31x10.5x15 mud tires and have a 2" TT and 3" drop shackles and my stock gearing is 3.73. and this thing runs like a beauty. still got pleanty to out run my brothers 99 f250 with a 4.6. and crusin on the freeway im at 65mph at about 2100 rpm, my last trip was...