Fuel Mileage with Ram 2500 6.4 HEMI HD vs Cummings Diesel

[Tank6370]

Is anyone pulling a fifth wheel around 15k pounds with a Ram 2500 with a 6.4 HEMI HD or Cummings Turbo Diesel? I am just wondering how the fuel mileage is on average for either engine. We are looking into getting a Ram 2500 to tow a camper and have to decide on the motor we want. Thanks for helping us out.

[TXiceman]

How often will you be towing the trailer?  Personally, I'd want a diesel for more than a weekend trip.

Ken

[Jinx & Wayne]

You don't mention a year or model, but gas or diesel, a 2500 is probably not enough truck for a 15k fiver.  Payload and axle capacities are probably too low.

Wayne & Jinx
2017 F-350 diesel, dually
2006 Carriage Carri-Lite 36KSQ

[podwerkz]

No 'g' in Cummins. 

[NDBirdman]

A Cummins 6.7 in a RAM 3500 is your best bet.  Yes, that 2500 can pull it, but up/down hills/mountains, heavy cross-winds and emergency stopping even with camper brakes....  I pull a camper that would have been doable with a 2500 but on steep grades... I'm very happy I went overboard and bought a RAM 3500 DRW.  And to your question, gas is good if your going to be doing a lot of unloaded driving with it but for torque up said inclines/long distance, diesel is better.

Edited December 2, 2021 by NDBirdman

[markandkim]

Get 24 MPG everyday driving and 14 MPG while towing a 10K trailer. Average for my 2020 Ram 2500 6.7 Cummings.

When I had the 2016 RAM 2500 5.7 gasser, I got 15 everyday and 9 towing.

There are many reasons to consider the diesel. It will even save you money. I know there's a  night and day difference while towing.

[rbertalotto]

I've had both......My trailer is a bumper pull of 8K pounds.....No way I'd pull anything over 10K with a gas. The 6.4 Hemi I have now is a great tow truck...But it ain't no diesel! For around town, non towing...I love the gasser....But everytime I tow, I miss my diesel....

BTW, I'm on my second 6.4. I had a 2018 and now a 2021. The 2018 had a surging problem that the dealers (two of them and 12 weeks in the shops) couldn't fix. At 40K miles I traded for the same truck in a 2021. Well at 15,000 miles is started doing the exact same thing....It does it unloaded and much more prevalent while towing......I finally figured it out...High Test Gas....While on a long trip I decided to use High Test to see if it made a difference. After two tanks the surging was gone! And the truck is WAY more responsive and much quicker when not towing!  So now the less expensive fuel, compared to diesel is a wash...UGH!

Come spring, I think a Diesel is in my future....Again!

[Consolenut]

Gas engine if geared right can tow no problem.  I have an 4500 with the 8.1L. 6 speed Allison and 5:13 rear gears. my Teton weighs 25k. With 6400 on the pin. And it goes just fine.  Let the gasser rev to peak torque and let it roar.  For the difference in the gas engine cost vs diesel you can buy a lot of gasoline.

[TXiceman]

41 minutes ago, Consolenut said:

Gas engine if geared right can tow no problem.  I have an 4500 with the 8.1L. 6 speed Allison and 5:13 rear gears. my Teton weighs 25k. With 6400 on the pin. And it goes just fine.  Let the gasser rev to peak torque and let it roar.  For the difference in the gas engine cost vs diesel you can buy a lot of gasoline.

Wondering what kind of average speed do you run and what is your MPG?  I spoke at length to a fellow with a 3500 GMC dually with the 8.1L and a 18,000 lb. trailer and he said it pulled fine, but he could pass everything except a gas station.  We were getting close to 10mpg pulling a 16,500 lb. trailer with our 7.3L Ford diesel running 65 mph.  He was getting half that towing and about 10mpg running solo.   

[rbertalotto]

Just as a data point...same 8k pound toy hauler trailer....both diesel 5.9L and gas 6.4L did multiple cross country trips from Massachusetts to California....Diesel got 12-13 mpg at cruise set to 65mph...gas gets 10 mpg. Unloaded both get 17mph at cruise set to 65mph. But, the diesel very rarely down shifts. Even in western mountains. 1800 rpm the whole way. The gas engine sounds like it will grenade when trying to maintain anywhere near 65mph pulling the western mountains and many eastern mountains. Gas engine constantly shifting. Diesel was 2006 with 5.9L/373 gears....Gas is 2018 or 2021 with 6.4L/410 gears.

Edited December 5, 2021 by rbertalotto

[rbertalotto]

Article I wrote about RAM towing real world.....

http://rvbprecision.com/rv-projects/ram-2500-6-4l-hemi-mpg-observations.html

[Jinx & Wayne]

11 hours ago, TXiceman said:

Wondering what kind of average speed do you run and what is your MPG?  I spoke at length to a fellow with a 3500 GMC dually with the 8.1L and a 18,000 lb. trailer and he said it pulled fine, but he could pass everything except a gas station.  We were getting close to 10mpg pulling a 16,500 lb. trailer with our 7.3L Ford diesel running 65 mph.  He was getting half that towing and about 10mpg running solo.   

I didn't chime in about mileage before because I have the Ford 6.7 diesel.  Trailer is 16,000 or so.  Unloaded is about 15-18 mpg. Towing is 10-11 mpg.  I have no trouble with fuel stations because the 350 dually gives me enough payload for a 50 gal Transfer Flow low profile tank.  I have a range of about 850 miles towing (34 main plus 50).  The fastest I travel is 62-63 mph except to pass.  The 6.7 passes very well.

Wayne & Jinx
2017 F-350 diesel, dually
2006 Carriage Carri-Lite 36KSQ

[whj469]

I would not get a 2500, I moved up to an F350 for a 16,500 fifth wheel. I get milage about what is noted above. Diesel is the way to go.

[gjhunter01]

A diesel will last 500k miles if you take care of it and then the resale will be higher with a diesel which will offset some of the original purchase cost. Comparing a diesel to a gas is like oranges to apples!

I have a 100 gal aux diesel tank in the bed of my Chevy DRW which makes refueling for any trip under 1400 miles, a non issue. Not to mention the cost savings benefit of stocking up in cheap fuel areas. I'm sure a 100 gal aux tank of gasoline would not be a wise move in the back of a gas engine truck. Some thougts to consider.

Edited December 6, 2021 by gjhunter01

[Consolenut]

On 12/4/2021 at 9:34 PM, TXiceman said:

Wondering what kind of average speed do you run and what is your MPG?  I spoke at length to a fellow with a 3500 GMC dually with the 8.1L and a 18,000 lb. trailer and he said it pulled fine, but he could pass everything except a gas station.  We were getting close to 10mpg pulling a 16,500 lb. trailer with our 7.3L Ford diesel running 65 mph.  He was getting half that towing and about 10mpg running solo.   

keep in mind my overall weight combined is just over 35k .. my 5ver weighs 25k alone. Not sticker but scaled at cat scales. I get 7-7.5 pulling 65-68mph. My truck has a 53 gallon tank from the factory.  It might due better if I pulled faster because I'm at the bottom of the torque curve at those speeds. Still not complaining at that weight.

Edited December 8, 2021 by Consolenut

[Consolenut]

On 12/5/2021 at 11:40 PM, gjhunter01 said:

A diesel will last 500k miles if you take care of it and then the resale will be higher with a diesel which will offset some of the original purchase cost. Comparing a diesel to a gas is like oranges to apples!

I have a 100 gal aux diesel tank in the bed of my Chevy DRW which makes refueling for any trip under 1400 miles, a non issue. Not to mention the cost savings benefit of stocking up in cheap fuel areas. I'm sure a 100 gal aux tank of gasoline would not be a wise move in the back of a gas engine truck. Some thougts to consider.

For the record I put 505k and 561k on my last two gas engines  No rebuilds never took the valve covers off.  Only replaced one transmission.  Both 7.4L vortecs aka 454's. Would still be driving one but I upgraded to the 4500 and the 8.1L. now I've got more rear gear, air ride seats and an air ride tslb hitch 

[markandkim]

4 hours ago, Consolenut said:

For the record I put 505k and 561k on my last two gas engines  No rebuilds never took the valve covers off.  Only replaced one transmission.  Both 7.4L vortecs aka 454's. Would still be driving one but I upgraded to the 4500 and the 8.1L. now I've got more rear gear, air ride seats and an air ride tslb hitch 

The fuel savings alone would have paid for 2 diesels. Even @ 250K miles.

Gas engines just waste a lot of fuel and are white knucle to drive in comparison.

[Consolenut]

The 8.1L and Allison 6 speed are awesome.  The downshifting and grade braking alone rival any diesel.  I like listening to the 8100 roar up a grade at 3200rpm.  The diesel clangity clang clang is what I don't care for. 

Lol in comparison I saved almost 12k going the 8100 route as compared to dmax.  Difference being paid for vs a loan. 12k I've done lots of traveling, bought air ride seats all kinds of goodies. Not including the interest on a 5 year loan. Gas has it's advantages.

[gjhunter01]

15 hours ago, Consolenut said:

For the record I put 505k and 561k on my last two gas engines  No rebuilds never took the valve covers off.  Only replaced one transmission.  Both 7.4L vortecs aka 454's. Would still be driving one but I upgraded to the 4500 and the 8.1L. now I've got more rear gear, air ride seats and an air ride tslb hitch 

It can be done, but that many miles on a gas engine is the exception, not the norm like on a diesel. Usually a diesel will out last the truck itself and the resale on a 500k mile gas engine can't be that good! Gas engines have their place in transportation, but diesels were made for heavy loads, just look at any long haul semi. That said, if it weren't for my 16k fifth wheel, I would own a gas truck.

My chevy DRW 2018, gets 11-12 mpg with a scale weight of 27k at 60 mph, although a head wind can drop me into the 9's mpg.

Edited December 9, 2021 by gjhunter01

[steiny93]

last couple 5th wheels were 15k lb or above, pulled them with a pile of different tow vehicles

- ram 2500 with the 6.7 diesel

- gmc 2500 with 6.0 gaser

- volvo 610 with cummins ISM

 

The 6.0 gaser was under powered and really didn't like wind or hills.  Mileage in the 4-6mpg range, it wasn't enjoyable at 15k lbs.

The 6.7 diesel had plenty of power and pretty decent engine braking.  When the load cleared 20k lbs more truck would be better, but it wasn't a power issue.  More so braking and engine braking.  15k lbs it would get 7-9mpg.

The ISM was great for eating miles on the interstate.  9-11mpg with the 24k lb trailer, insane engine braking and very stable.

[Consolenut]

On 12/10/2021 at 3:39 PM, steiny93 said:

last couple 5th wheels were 15k lb or above, pulled them with a pile of different tow vehicles

- ram 2500 with the 6.7 diesel

- gmc 2500 with 6.0 gaser

- volvo 610 with cummins ISM

 

The 6.0 gaser was under powered and really didn't like wind or hills.  Mileage in the 4-6mpg range, it wasn't enjoyable at 15k lbs.

The 6.7 diesel had plenty of power and pretty decent engine braking.  When the load cleared 20k lbs more truck would be better, but it wasn't a power issue.  More so braking and engine braking.  15k lbs it would get 7-9mpg.

The ISM was great for eating miles on the interstate.  9-11mpg with the 24k lb trailer, insane engine braking and very stable.

Only diesels I'd own are a sport chassis 8.3L Cummins or a Volvo with a D13.  F350 F450 pickup can't handle my piggy pin of 6400 empty tanks. Not even the Dodge air ride 3500 can handle it. And yes I've had a few try it. Buried bumpers lol. My truck squats maybe an inch. Being I'm not a Ford guy nope. And the 6.7 Cummins is good but 90k or more for a new 4500 dodge no thanks.  I'll stick to a used MDT or HDT. More truck for the money. To each his own.

[GlennWest]

On 12/8/2021 at 11:12 AM, markandkim said:

The fuel savings alone would have paid for 2 diesels. Even @ 250K miles.

Gas engines just waste a lot of fuel and are white knucle to drive in comparison.

Don't think so. I towed my Teton, 21k, for about a year or with a 2012 Duramax. 5-6 mpg best I got towing. My Freightshaker does a little better and cost many thousands less.

[NDBirdman]

Tis the season for one hit wonders..... just saying.

[motojavaphil]

I had a Dodge V10 years ago and I got to know folks who run the gas stations pretty well.  Planning a trip was being able to make sure a gas station was near.  The Cummins sure made life easier.  It is thirsty as well, 2016 gets 10-13 mpg towing whereas the V10 gave me all of 6 mpg.  I know times have changed, with better mpg for gas,  but the lessons of towing with a gasser vs a diesel remained ingrained.  Not to demean a gas engine but it is for town trucks versus the diesels for cross country and country work.  I can appreciate the folks who get the 18 Wheeler but wife would not drive one as we thought about it.  

[gjhunter01]

My son is a owner/operator of a 2001 Freightliner and some years spends $20-30K for maintenance. Granted he will run 100k miles a year (1.6M on the odometer) and can gross well into the 6 figures for income. A high mileage semi may be a good initial buy and you may get lucky for awhile, but when the repair bills do happen, you will need some deep pockets.

My brother had a 2012 Volvo and he overran the RPM's in Colorado on a down grade, that one incident cost him $30k for a replacement motor! It was due to inexperience but still a costly lesson. Nobody is born with the skill to operate a big truck and it is a given that there will be expensive lessons learned acquiring that skill, even the best drivers make expensive mistakes.

I like my Chevy duramax and most passengers can't believe its a diesel since its so quite and no smell. My biggest concern is someday filling it up with gas, because I forgot its a diesel!! The Duramax L5P is a towing beast yet drives like a luxury sedan, and it should for the price it cost. Having the right tool for the job is usually the cheapest option in the long run.

Edited January 2, 2022 by gjhunter01