In shock and a migrane!!

[Daw14]

Maybe let it break in first, it may not go in the direction you want with a gear change.

 

[retired]

I would wager there is literally only tenths difference between 3.73 and 4.10 and actually might be in favor of the 4.10's under most conditions especially with 35's.

 

[ticat928]

As my Avatar shows when new I regularly got 24.5 mpg on regular 1,200 mile north south round trips, average speed 58 mph due to lots of construction and hour long border crossing, most of the time I am doing 75/80 when i can. Trip usually takes 12-hrs one way.
Fast forward, modifications bug hit me, got 20" wheels with very sticky larger tires.
My average mpg dropped to 19.8 mpg. The ultra low rolling resistance 18" OEM tires sure got good gas mileage, but locked up every time i hit the brakes, happy with the trade off, do not need to run into back of a Prius with an 8,000 lb truck

 

[ticat928]

pictures taken just now

 

[bsheen]

Not going to happen. At 65 mph 4:10s run 160 rpm higher in 8th than the 3.73. My 3.73 are doing 1600 rpm at 65 so your 4.10s should be 1760 with 33 tires. With you 35s you are probably close to 1600 already. . See picture above. People get way over involved in a gear ratio difference that means basically nothing. We aren't running 3 or 4 speed automatics anymore.

Cruise set at 70 I'm turning 2000rpm with the 4.10 on the flat. Incline of 2% kicks it up to 2500rpm

 

[retired]

Cruise set at 70 I'm turning 2000rpm with the 4.10 on the flat. Incline of 2% kicks it up to 2500rpm

so using a gear calculator in 8th which is 0.67 to 1 and 410's at 70mph with true 35's you will be 1846 rpms. with true 33.5 which is what most 35's are 1928 rpm and 32.3" tire will get 2000 rpms at 70. 3.73 in 8th with 33.5 is 1755 rpms. If 2% grade is kicking you to 2500 means you are dropping to 7th gear ie 0.84 gear ratio and I bet 3.73 would be hunting even more. kind of cool to play around with these calculators. https://purperformance.com/p-29669-rpm-calculator.html

 

[bsheen]

so using a gear calculator in 8th which is 0.67 to 1 and 410's at 70mph with true 35's you will be 1846 rpms. with true 33.5 which is what most 35's are 1928 rpm and 32.3" tire will get 2000 rpms at 70. 3.73 in 8th with 33.5 is 1755 rpms. If 2% grade is kicking you to 2500 means you are dropping to 7th gear ie 0.84 gear ratio and I bet 3.73 would be hunting even more. kind of cool to play around with these calculators. https://purperformance.com/p-29669-rpm-calculator.html

That is a pretty cool tool! So based on that its about a 200 rpm difference between the two ratios. Which I'd think that would translate to a decent savings?

 

[raggdoll]

What kind of mileage does a diesel version the Ram 3/4 truck with a crew cab get?

My 3500 6.7L bested at 23 mpg, no load, 65 mph hwy cruising

 

[MoParts]

What kind of mileage does a diesel version the Ram 3/4 truck with a crew cab get?

1-ton SRW, 13-15 on local mountain roads 17-19 highway.

 

[bsheen]

My brother in law has a '17 3500 6.7L Diesel, he was getting about 21mpg on a road trip we took from Watertown, NY to Southern PA. Which is basically downhill to PA and uphill on the way back.

 

[Forrest Alley]

Well i will say it does get better, when i pick up my 2020 2500 6.4 on January 12 2021 it was averaging 14 to 15. Then when i hit 10,000 miles I was getting 17 to 18. Towing my 24ft Taylor i get 13 mpg. Today i was 40 miles from home and had to stop and fill up, the trip home was pretty much flat roads, i set the cruise control at 55 and average 21 mpg. The truck now has 27,000 thousands miles on it. I have noticed at 55 the gas mileage is better, at 70 she average 17 mpg. Good luck with your.

 

[Maddamnmike]

None of the big 3 publish fuel economy figures for their HD trucks… (news flash: none of them are good)

I‘ll wager that you‘ll probably spend $15000 to drive 60000miles….

Correct. A HD does not have to report fuel economy. The laws are complicated for HD weight.

 

[HEMIMANN]

Appreciate the replies! MPG shock has definitely subsided a bit. Clearly I'm chaulking this up to a learning experience. I went with the 4.10 because I thought I NEEDED it for the 6-7k lb trailer I tow. As I mentioned I generally pull it and drop it for extended periods of time. I wasn't thinking of how it(4.10) would affect MPG. I just knew it was better for pulling. And yeeeesss I did put 35s on it, because it looks fantastic. Though, if the Night edition package came on it to begin with, I would be riding on factory tires. But because my heart was telling me I wanted the Night Edition, I spent a stupid amount of money blacking the thing out myself, by buying all of the badging, wheels and tires, grille etc. and then paying the dealer to put it on. Thats a totally separate topic....

I do have a question...I truly believe the 3.73 woud be plenty for what I do. (all kidding aside the 1500 woud be plenty) After running the numbers of parts and labor to switch to the 3.73 ($1500), it looks like I'd recoupe that cost after the first year. Is it resaonable to think I'd see 3-5 mpg improvement? If so, it seems like it woud be a no brainer for my situation. Unless there is something I'm not thinking of?

Again totally appreciate everyones input!

I have your truck but with 3.73 axle. I wish I had 4.10 because I pull trailers up and down the driftless (unglaciated) regions of Wisconsin - with the 6 speed transmission, the gearing is wrong for 3.73 axle. It constantly hunts. If it had the 8 speed ZF transmission, it would be fine.

Before I went from stock Firestone Transforce AT tires (junk), I got 16.5 mpg unloaded in summer, and 11 mpg loaded regardless of season. Those tires are hard with little traction.

When I switched to real AT tires (General Grabber ATX), mileage dropped 1.5 mpg unloaded - understandably so, as they are true AT's with softer compound and lots of tread blocks and sipes. No impact when loaded.

I would not go to 3.73 axle unless you don't plan to tow in hilly regions.

 

[ticat928]

My 3500 6.7L bested at 23 mpg, no load, 65 mph hwy cruising

23 miles per canadian gallon = 19 miles per US gallon which is still pretty good

My Dealer told me 95% of his customer in the last 5 years claim 18 mpg is the best they can get
looking at this forum it seems mostly true

 

[Scott0700]

I’ve had several gas 3/4 tons. Always got 12mpg overall. Mostly used them as daily drivers. Very infrequently towed heavy. But when you need it, you need it.
If you are unhappy with it, take it to a couple of dealers and Carmax. Last two 3/4 ton trucks I sold, (within the last year) I sold for more than I paid for them new.

 

[Irishthreeper]

It was only 68 miles but today my 2500 Hemi got 19.9 (20.1 at one point). Most of the trip was 58-68mph on cruise but there was one town to go through. Mostly flat roads. Numbers are from the lie-o-meter but I was still happy with it. ‘21 2500, 4.10’s. The MPG is crazy dependent upon how heavy your foot is!

 

[bsheen]

It was only 68 miles but today my 2500 Hemi got 19.9 (20.1 at one point). Most of the trip was 58-68mph on cruise but there was one town to go through. Mostly flat roads. Numbers are from the lie-o-meter but I was still happy with it. ‘21 2500, 4.10’s. The MPG is crazy dependent upon how heavy your foot is!

That's outstanding!! Gives me hope!

 

[Justin33]

Fill up reset the trip meter set cruise at 60mph and don't stop for 200 miles. You will get much better than 10mpg. I have 35's and speedo calibrated for correct tire size.
View attachment 485967

what the heck I feel my ram never did better than 10 city driving and now with 4” superlift I’m getting 7.5 with 275 65 20’s

 

[Doug Ram]

Even the worst MPGs you guys are getting in your heavy duty trucks (gas or diesel) are so much better than the godawful gas Ford 350 I drove 30+ years ago for a construction company.

 

[wyo2track]

A 3 day trip to eastern wyoming and back to the west side. Crossed 3 mountain ranges, battled wind, snow, 65 to 75 mph speed limits, morning temps in the single digits warming into the 30s. 2014 with 4.10's. The 6.4 is most efficient when temps above 50. Wish I had the 8 speed when towing and climbing alot of grades, otherwise it's fine.