Anyone know of a after market company that make's them other then the factory one's the dealership wants 550.00 for them?
I'm getting about 12mpg with these, not to happy

Thanks
Chris

 

While the 3.73s will improve your fuel ecomomy somewhat, I don't think the extra expense of changing the ring and pinion will be cost effective. The single most important determinant if fuel ecomomy is the driver. Even 3.73s will consume lots of fuel if you have your foot in it. Also, is the engine broken in? What percentage is city driving? Casey

 

You don't say how new or how many miles your truck has, but my 555 w/4:10 gets 17+ miles in mostly short trips to town and hauling building materials etc. I've yet to take it on a long trip, but the MPG is improving with every tankfull as long as I keep the RPM's below 2000 or so. Nat

 

Chris,

Don't jump into this. You didn't list enough info on your truck to really comment, but . . . . mine got 12.4 on the first measured tank and 12.7 on the second (didn't check the delivery tank because I didn't know how full the dealer filled it) and I have the 3.73s. I just turned 1000mi. and this is pretty much stop and go traffic. I'm really hoping for some improvement as she breaks in.

Neil

 

Might be cheaper to just do a tire swap. Go to 315's. However, your frontal area will increase and may offset any gain from lowering the RPM's. Also the torque required to move the truck along at any given speed will still be higher with the tire swap vs the gear swap. Gears is the right way to do this.

If you do decide to lower your gearing, your engine will probably thank you for it. It will see fewer RPM's over its life span.

Also...while you are in the axles, might as well to ARB lockers or similar. I hear the stock units aren't all that great.

 

I put 315's on mine and lost 1 to 1 1/2 MPG. They are not for mileage. Too much rolling and wind resistance.
I also have the stock LSD diff and love it. Simple, effective, and silent. And much less strain on the axles than an ARB. ARB's are great for rock climbing in Jeeps where the truck weight is low, but locking the axles together in a Dodge with a fifth wheel or other heavy load attached would put an astronomical load on the poor axle.

Wetspirit

 

I tend to disagree here. ARB's are for people who take their truck off-roading and will work in any truck...not just Jeep's. If you don't see snow, mud or rocky terrain then yes it's not required. If your pulling a 5th wheel, I don't see you going through the above conditions and really don't even need a locking diff. Having 4wd and the extra weight of the 5th will prevent either rear wheel from spinning so any sort of locking or limited slip diff really isn't even needed. However...if you are nuts enough to take your 5th through the mud bogs then I wouldn't do it without a locking ARB - period.

I wonder what axle carriers the people who do truck pulls use?

The advantage of the ARB is you can unlock it for highway and street use. This puts even less strain on the axles and drivetrain when any sort of limited slip diff really isn't required.

Its important to match your equipment to your lifestyle.....not get stuff just to brag about what you've got.

As for the larger tires.......I have mine sitting in the garage waiting for my Bilstein Superlift kit so can't comment if this would increase or decrese mileage. Seems some people do and some don't. Other factors come into play like city/highway useage, driving style, etc. In my opinion, I believe I'll see an increase in mileage for highway use and a significant decrease in the city. Overall.....we'll see what it does to my MPG!