Gottcha, gears would definitely help you out, so would a transmission tune to adjust your shift points and Torque Converter engagement a little more optimally, other than that gears might help you get a little better fuel economy, but it wont be more than 1-2 MPG....

Real gains are had at keeping your engine running as efficiently as possible, by maintaining the condition of the internals of your engine and drivetrain.

 

Yea I've played around with the tranny tuning a bit on my bullydog triple dog tuner but don't fully understand what I'm doing