I have seen plenty of 4.10 geared trucks become re-geared for just your reason - mileage! I'm thinking about re gearing mine just because the truck has plenty of power WITHOUT that steep gear, I run out of gear way too quickly and its dangerous pulling at 55-60 when everyone is flying around you at 70-75, and all you're trying to do is get some fuel mileage! There are 3.42's, 3.73's and possibly even some more ratios out by now and they run you about $300.

 

You can't spend your way out of this. The money you spend will never be recouped.

The best way to get better mileage is to buy taller not wider tires. Run what you've got when you need new tires buy taller ones. Then if the tires you choose cost more than direct replacement that's the only money you have to recover.

You are running 4:10's the cost to lower the rpms with gears will not be recovered in mileage increase for many miles if at all.

How much does a "box" save you? I'm not going to do the math but if you get 3 more miles to the gallon how many miles will you have to drive to recover your investment. OH and if something breaks so much for your warranty.

 

8mpg vrs 10mpg with diesel at $3.25 a box should pay for itself in 10,000 miles

I have owned 4 Dodge trucks I am not going to loose any sleep over a possible breakdown or lose of warranty .

 

Assuming you have the 4 speed automatic, make sure you get it to shift into overdrive at 50 mph then drive no faster than 49 mph, slower preferred, set the cruise, reset the overhead mpg, and then using the cruise control down speed button reduce your speed keeping the rpm to just above 1000 rpm. Try (ha ha) to drive on as flat as possible roads with little or no load. In other words the impossible. Oh yea, I forgot always drive with a tailwind and drive only east. OH, Yes,...Good Luck!

 

How about the GearVendors overdrive? Anybody had any experience? They make some wild mileage claims; Seem to me if you drove a hundred miles at 50 mph, you would get an idea of what mileage at 1600 RPM would be like. But then that's $3K...

Also, hows about free wheeling front hubs? Seems that should be good for at least 1 mpg?

 

And don't forget to leave the tailgate open

 

I use to get around 12.7 mpg. empty @ 70 mph. @ 2500 rpm. after Super chips , 5 inch staight piped, AFE stage 2 intake, silencer ring removed I get 20 mpg at 70 mph. but I have 315/70r17 bfg all terrains that changed the 4:10 rears to 3:83 or some thing like that. but when towing it drops alot about 13mpg. I had it drop to 5 mpg. when I towed a 20 foot container full of alot of furniture on a 32 foot gooseneck that was a night mare for 900 miles!!!!

 

LUIS when kind of fenderflares are on the back of your dually???????????

 

Guy in our chapter has a 12v 2x4 5 speed (he calls it an 8 speed) with the Gear Vendors and gets 24.5 mpg.

 

My truck is all stock, and I get 17 MPG in town and 20 MPG on the hiway. I also get 13 MPG when I am pulling my RV . See my Sig.

 

I consistently do between 15.1 and 15.3 week after week in 60 city/40 highway driving. I got 17.2 once on all highway and a few 16.x's but 15 is the most consistent.

 

I'm getting 21.3 mpg. I drive 65 to 68 mph. Manuel - 4x4 - Banks intake to keep the cool air in - I noticed the biggest improvement when I took out the stock muffler. Keep the CAT IN. I took it out and noticed 2/10 mile improvement with three tanks of fuel. I couldn't stand the smell during warm up so put it back on. Driving style helps too.

 

Tough to point to a single magic bullet with fuel mileage. Every truck is different... But, most will agree the largest single factor is fuel mileage is the difference in driving styles. Those who can keep it slower usually post better mileage. Also, those that have 2x4's also do much better (less weight, etc). I too have been interested in the gear vendors for just the curiosity. The initial cost of $3K is steep, but could be recovered if one was to get 2-3 MPG improvement over a few years. Trouble is, haven't found anyone that has done this yet. Had one guy in my office seriously considering it, but he chose to buy a little fuel efficient car for the $3K he was going to spend and now sees 30 MPG. I also would be interested to hear if anyone has put this on a 3rd gen and what the results were?

 

Bushwackers for fleet side trucks took some time but they are on!!!!

 

Well I'm getting about 16 in town and 18 on the road with 3.73 gears at 16,000miles on a 2007 5.9 CTD. At 70 mph it's turning about 2200 RPM. Seems fast. A friend's Volvo/Cummins 18-wheeler turns about 1500 at 70MPH and will run all day long on cruise control while knocking down 6 mpg at 70,000 lbs. Scale that down and I ought to be getting over 150 mpg!!! Just dreamin'...