Bottom line, big cash out lay with no benefit in mileage and many additional modifications needed to strengthen the rear diff.
Go spend that money on a really good tune up, you'll get better gas mileage.

Well first off they are mis informing you.
1-These trucks are NOT all wheel drive as they state, they are full time four wheel drive. HUGE difference.
2-you need to remove your transfer case and install this thing because it goes inside your t-case.
Thats alot of work for a 1mpg gain.
So figure $500 for the part and shipping and install if you do the work.
If you have it done then you are looking at $1000 I am guessing in parts and labor.
So how long will it take you to recup your $1000 at a gian of 1mpg?
EDIT:shipping is included. But it is still alot of work for 1mpg.
A good tune up, full synthetic oils and lubes and a light foot will net you the biggest gain in mpg.

Thanks for your input Spike! I'm actually not doing to bad on mileage, just always thinking bout stuff. You and Disco Mike have been a big help.

Spike, forgive my ignorance, but would you please explain this statement to me?
1-These trucks are NOT all wheel drive as they state, they are full time four wheel drive. HUGE difference.
What is the difference b/w full time 4WD and AWD?
Thanks.

AWD uses clutches in the driveline, they detect wheel spin and they lock up and transfer power from one wheel to the next.
Also AWD cars do not have a hi/lo transfer case.
AWD=Subaru, great in the snow, wet roads, gravel...light duty, need extra traction.
Full time 4x4 is all gears, no clutches, gears, just like your grand dads old farm tractor, good old solid noisy heavy duty gears.
Most part time 4x4's also use clutches, any "shift on the fly" 4x4 has a clucth in the transfer case, push a button on the dash and the clutch engages and you are now in 4x4 mode.
How sturdy are clutches? Not very.
Does that help explain it alittle better?
Gears dont slip, gears rarely break, gears are reliable, I like reliable, I am reliable, to reliable so I have been told.

Isn't the Differential a clutching system? Isn't that why we don't get "Bind-up" on tight dry corners, unless you actually engage the Lock?

best line EVAR!

No.

Our transfer case acts just like our front and rear open differentials, allowing us to have 4x4 permanently with no option of engaging/ dis-engaging it like Jeeps and NOT having "bind-up" on dry corners.

When we lock the transfer case we force the front and rear drive shafts to turn at the same speed at which point you would experience "bind-up" on corners.

But in the case of my 03, no cdl, not even the option unless I break open my tran case. Open diff in the center means power shifts between front and rear. So not really true 4wd yet, right? At least the way I understand it. Please correct me if I'm wrong.

Hooray 4 avatars!