All this talk about 4.10 gears being put into your vehicles has me considering it seriously....but only one worry...and I haven't found or if i did remeber how much gas mileage I will lose on the highway with this change...What are the differences on the highway at 60 -65MPH in overdrive RPM wise?
And will it give the truck more acceleration from a stop without the load too?...

 

The engines of today make their torque peaks at a significantly higher RPM than the older engines. This means that when going to a lower gear you are actually moving closer to the torque peak which is the most efficient speed of the engine. Your fuel mileage will not fall off and could even improve with a lower gear. This doesn't, however, mean that you can go to 5.88's or something without losing fuel mileage, but a slightly lower (higher numerically) gear will probably not hurt anything.

Good luck,

 

I believe that you will only see about 400 to 500rpm more @ highway speeds.