I Am Buying A New Dodge 3500 Cummins. I Will Be Pulling A 5th Wheel Toy Hauler That Is About 8000 Lbs Dry So I Figure About 10,000 Loaded. I Will Also Be Driving It For My Everyday Truck. Gas Milage Is Important For Every Day Use. Should I Get 4:10 Rear Gears Or 3:73 Rear Gears. Dealer Tells Me I Will Have To Order This Truck If I Go With 3:73, There Is Not Any Around All The Trucks Seem To Have 4:10. Which Rear Gears Should I Get, And Is The Gas Milage Much Different Between The Two.

Since the trucks have overdrive, I don't believe there's much difference in mileage. The 4.10 might be a little better for real heavy loads. My 2500 has auto and 4.10's. Gets around 13 towing 7k pounds and 15-16 in town. Haven't checked on the road since ECM re-flash.

3.73 if your going to leave the tire size stock. If your going to lift the truck or put bigger tires on it, 35' or larger, then get the 4.10. The 3.73 are more then enough to do the job.

get the 373 anytime you go over 2 grand on the tack you start burning more fuel.and if you are getting the 6 speed its overdrive is not as high as the auto.

I have to ask the question, why a 3500? only 8000 - 10,000 lbs. would be fine with 2500, and better for daily driver.

I've often wondered when I should make the move to a 3500. I pull heavy and never seem to need more. Any ideas???

Good info about overdrive on autos and 6 speed. I'm running 2k rpm at 75 mph on the auto. Finally did a road trip yesterday and got 19 mpg with cruise on 72 mph. That's from the trip computer and not hand calculated so 'your mileage may vary'.

The weights you suggest require the 4.10 gear in the General Motors world not sure what Dodge requires. Have your dealer show the trailering Guide for Dodge and you can determine which gear is required for 3500 Cummins to pull the weights you are talking about.

with the new G56 manual 6 speed trans, 4.10 gearing is not an option... only avalable gearing with the g56 is 3.73... if you are going auto, either will be fine, but if you are planning on going with larger than stock tires [like the popular 315/70/17's] 4.10's would be nice

:cool2: :ro) Duals Are Cool.