Fuel Mileage 2002 HO?

[Diesel12]

I am curious if I am making a major sacrifice trading my 2000 5spd. for a 2002 6spd. HO for fuel mileage?

 

[DHatfield]

I would have to say that your mileage will be about the same since the 5 speeds 5th gear ratio is 0. 75 to 1 and the 6 speeds 6th gear ratio is 0. 73 to 1. So in short your RPM will not drop much at all assuming both trucks are equiped with the same axle gears. If you have 4. 10 and go to 3. 55 then you may gain mileage then otherwise not really worth it in my opinion. But then again you would get rid of the possible 5th gear going out.