I posted this in the "no engine, no trans" third gen forum. It kind of belong there (diffs) and here as well (trans).
I have an 06, HO, 6 speed manual 4x4 with 3.73s. The truck needs another gear at highway speeds! I'm turning about 2400 RPMs just to keep up with traffic at 75 MPH. If I'm late and I need to move, it's even worse.
Please, save the e-mails and posts telling me to slow down. The safest speed is with the traffic around you. If that is 65 MPH, I go 65 MPH. If that is 85 MPH, I do 85. If it's an empty highway, I do about 10 over the posted limited (maybe a little more if I'm late).
I drive about 45k miles a year, mostly highway, so if fuel is $3 a gallon a 3 MPG savings (from 16 to 19) means about $1300 a year.
I have found this overdrive:
http://www.drivetrain.com/new_overd...dodgmanual.html
I figure (with shipping, handling, shortening the drive shaft, and $400 for an install) this unit will cost me about $3700. It will take me three years to pay it off (in fuel savings).
The problem is:
-I want to wait until my warranty is over to modify the truck (2 years)
-Three more years to pay for the unit (truck would then be 5 years old and have 225k miles on it)
-If I keep the truck until 300k miles I've only saved about $2200 in fuel total.
My questions are:
-Has anyone used this overdrive? What do you think? What type of milage do you see?
-Is the final drive of 2.13 (with my trans and axels) possibly too tall?
-Would it be easier/less expensive to change my diffs out to a taller ratio? Is there a 3.53 (front and rear)for my truck? I belive I have the 11.5" rear end.
-Any other thoughts?
Linear Mode
