6.4 vs 5.7 Dodge Engine

[Wrench & Ride]

Looking at a 3/4 ton and looking for some insight from anyone that's had one or both of these engines. Big difference in power or fuel economy? Any major issues you've had with either? Ideally I'd like a Cummins but the budget might not allow it at the moment. Truck will be a daily driver and pull a sled trailer through the mountains 4 or 5 times a year and likely a few loads of cattle throughout the year. Thanks!

 

[rhody605]

I have the 5.7 in my 2500. Crew cab long box.

I’m quite sure mine has 3.73 gears which works great for highway or driving to work.

Avg. 14-16L/100km. Empty

Hauling the 4place enclosed is 28L/100km.

I wish mine had 4.10 gears for towing.

I had been curious of the 6.4L myself.

Mine when towing feels sluggish in the higher gears. But I can put the pedal down and it hauls ass towing. But just sucks back the fuel.

But mine is a 2012 and got it this summer for only $10k. A diesel would be min $20k. Big difference.

 

[Stg2Suby]

On the gas vs diesel subject nobody seems to mention that diesel costs $30c per liter more than regular gas all winter long.

 

[mountainsledmania]

yea but regular gas is nowhere near as energy dense as diesel, so even if you were saving 30c plus... it would still be cheaper to run the diesel fuel mileage wise.

 

[Stg2Suby]

yea but regular gas is nowhere near as energy dense as diesel, so even if you were saving 30c plus... it would still be cheaper to run the diesel fuel mileage wise.

Fair enough, I'm just bitter I guess thinking back to the good old days when diesel was $10c cheaper than pump regular gas.

 

[rhody605]

Fuel mileage wise diesel will always win. But at times it has been 30c per liter more and vehicle costs $10k more in the used market. So would take a really long time to make up that difference in my opinion.

Plus added expenses for maintenance.

I love diesel when it works. Good mileage and hauls like a beast, Hate it when it needs to be fixed.

 

[ATV Rancher]

Have a 2014 Ram 1500 with a 5.7 that an employee drives, with 100,000 miles on it. No trouble, but never pulls anything. He says it has good power.

Had a 2015 Ram 2500 with a 6.4 that my son drove. Had lifters replaced under warranty and at ~50,000 miles it ground up the transmission. Traded it in at that point for another GMC. There were others like it on the back lot with the tranny out, as well. Didn't pull real great but would do the job.

I've read where GM is supposed to come out with a bigger gas engine for their HDs in another year. I would consider waiting for one of those, but the 6.0s are rock solid.

 

[Mach1]

I have 6.4 3500 and love it, on Hwy I get great mileage if under 120km and in town same as 5.7 in city. I have been 1 week and use 5/8 tank to job and back, filled up last Monday full so 1 week today. All city driving

 

[acesup800]

On the gas vs diesel subject nobody seems to mention that diesel costs $30c per liter more than regular gas all winter long.

I guess it depends on which province. In BC, diesel is par or even a bit cheaper than gas all winter.

 

[cutterguy987]

I have a 2500,6.4 I like the truck works good 90,000 + k on it now no problems at all . A lot cheaper to service than the diesel I had . Towing is not as good but I can deal with it.Truck has a lot of power. Wish I would of bought a 8' box 6.5 is little small for what I need .Use to be wife's truck , I use it for work now .not pulling my trailers it gets good fuel mileage , hook a trailer on it it uses fuel .I am really impressed with the suspension on it. Would not hesitate to buy another one but I would go with a 3500.

 

[dragonweld28]

I had a 2014 3/4 ton longhorn for 4yrs. It was a great truck. Sold with 200k on it. Averaged 16L/100k empty, so not bad for a 400hp gas motor. Towing was good until the wight was over 5000 lbs then it just didn't have the torque. Would average 28-30L/100km towing. Would be shifting between 3-4 gear all the time. Oil changes were cheap and very easy. I recently purchased a used diesel and did a few upgrades. If you can make it work, the diesel is worth the money. I average 10.8L/100km on the highway and it has a ton of power. I did delete it and run a 45hp tow tune with EFI live. 4" exhaust with muffler and EGR delete an transmission tuning. I can almost get 950km to a tank.

 

[tool_man]

I have a 2014 Ram 2500 with 6.4L and only run deck no real towing. Love it for that, its thirsty and powerful. Just did tranny under warranty with less the 80K on it. Wasnt impressed but no other issues.

 

[Wrench & Ride]

Does anyone have more details on the tranny issues? Was there a recall on something or was it just a few lemons that guys got unlucky with?

 

[1200]

I would get 4.10 gears . When put on some real tires on and tow it will be better.

 

[takethebounce]

I am always impressed with my buddies 15 3500 6.4. I am not sure of the gearing on his. Empty his mileage is just as good as my 3500 6.7, two sleds on the deck he is just a couple of liters over mine hauling around the same two sleds. Cost of the truck was a wash as I took advantage of the "free cummins" and some other discounts, he got a good price on his as well. The only reportedly difference with the 66RFE and the 68RFE is the torque converter. Nice thing when hauling sleds is you almost always have some fuel you can dump in the tank from a jerry can when you have a gasser lol

I haven't built one online but I believe if you opt for the 3500 you can get the AISIN if the truck is over 10,000 GVW, not that I would consider it a selling feature as I haven't liked any 3500 I have driven with that tranny.

The one thing I just am not a fan of is the 16 plugs, but as long as you get 100,000k out of them its only every few years you have to think about it.

 

[Panzerdog]

I love my 6.4 it’s awesome only complaint is it thirsty but not that bad there are worse trucks the gas chev 6.0 and ford 6.2 are both worse. The recall was a pain in the a$$ but once it’s done no problems since. Oh yeah can race a stock cummins to

 

[Cyle]

I am always impressed with my buddies 15 3500 6.4. I am not sure of the gearing on his. Empty his mileage is just as good as my 3500 6.7, two sleds on the deck he is just a couple of liters over mine hauling around the same two sleds. Cost of the truck was a wash as I took advantage of the "free cummins" and some other discounts, he got a good price on his as well. The only reportedly difference with the 66RFE and the 68RFE is the torque converter. Nice thing when hauling sleds is you almost always have some fuel you can dump in the tank from a jerry can when you have a gasser lol

I haven't built one online but I believe if you opt for the 3500 you can get the AISIN if the truck is over 10,000 GVW, not that I would consider it a selling feature as I haven't liked any 3500 I have driven with that tranny.

The one thing I just am not a fan of is the 16 plugs, but as long as you get 100,000k out of them its only every few years you have to think about it.

I don't buy that the empty mileage is the same. While I have not owned that new of a hemi or the 6.4 at all, every single one i've had the Cummins mileage empty is nearly 50% better. Roughly 500km to a tank compared to 750km with the Cummins on 90L. The more you load them down, the bigger the gap will be. Won't take much weight and the Hemi will be mid to high 20l per 100km. I see that mileage on my Cummins, but that is grossing around 30,000lbs.

Personally I wouldn't consider the AISIN in the hemi even if you can get it. 2500/3500 Hemis have no resale at all to begin with. Once they hit about 5-6 years old and 150,000km they are pretty much worthless. Decent trucks especially if buying used can get great deals, and they will pull 6-8k just fine if you're not putting on many miles the fuel isn't a big deal. But buying new? I would think long and hard to try and buy a 1500 instead, they hold their value so much better.

 

[takethebounce]

I don't buy that the empty mileage is the same. While I have not owned that new of a hemi or the 6.4 at all, every single one i've had the Cummins mileage empty is nearly 50% better. Roughly 500km to a tank compared to 750km with the Cummins on 90L. The more you load them down, the bigger the gap will be. Won't take much weight and the Hemi will be mid to high 20l per 100km. I see that mileage on my Cummins, but that is grossing around 30,000lbs.

Personally I wouldn't consider the AISIN in the hemi even if you can get it. 2500/3500 Hemis have no resale at all to begin with. Once they hit about 5-6 years old and 150,000km they are pretty much worthless. Decent trucks especially if buying used can get great deals, and they will pull 6-8k just fine if you're not putting on many miles the fuel isn't a big deal. But buying new? I would think long and hard to try and buy a 1500 instead, they hold their value so much better.

Rarely do I see 700 empty on my 16 3500 let alone 750 driving in town or driving as a daily driver with 80km round trips to work. I don’t drive empty on the highway for extended periods either, always towing or carrying something then. If the lieometer happens to say 750 to empty it never gets that, especially now in winter with idle time after work. This truck is 14-15L/100k empty. The only time I saw low 11-12 on the dash was an 80km/hr stretch of construction traffic which never seemed to end. Hand calculated it still was in the mid 13’s. The 6.4 is 15-16L/100K empty doing the same drive. Just because you have a Hemi doesn’t mean drive it like you stole it. If someone is going to claim that the Cummins is going to be %50 better than the 6.4 empty they should be able to back that claim up.

Two on the deck I can be anywhere from 18-20L/100km driving like I do. Holding to the speed limit where it never goes over 100 I can get just over 600km and that’s 100L of fuel so barely 17L/100 driving like a granny.

The 6.4 was 22-24. Big deal. Like I said a couple more L/100km for some guys it just isn’t worth the price to get into a diesel if there are no deals to be had. Winter diesel prices suck. Sure more energy per litre but, $100 + for two fuel filters once a year, more expensive oil changes if you do them at the same intervals as the gas truck, so comparing 18-20 to 20-24 on the high side isn’t that unimaginable.

These claims of some of these diesel owners are bs on their mileage. Stock trucks will never see these claims. Never do they show proof or their life fuel average. One time they get 800km on a tank with a tail wind being drafted by a semi and that’s the example they always use.

 

[NoBrakes!]

my brother had a mega cab blacktop for a few years, tranny let go of 3rd gear. he left the truck at the dealership and drove a new cummins out. said he would never go to the 6.4 again, no resale and paid a lot for it to be worthless once the tranny dropped. they gave him 10K for it I think and put it on a flatdeck with no tranny in it

 

[Dawizman]

Rarely do I see 700 empty on my 16 3500 let alone 750 driving in town or driving as a daily driver with 80km round trips to work. I don’t drive empty on the highway for extended periods either, always towing or carrying something then. If the lieometer happens to say 750 to empty it never gets that, especially now in winter with idle time after work. This truck is 14-15L/100k empty. The only time I saw low 11-12 on the dash was an 80km/hr stretch of construction traffic which never seemed to end. Hand calculated it still was in the mid 13’s. The 6.4 is 15-16L/100K empty doing the same drive. Just because you have a Hemi doesn’t mean drive it like you stole it. If someone is going to claim that the Cummins is going to be %50 better than the 6.4 empty they should be able to back that claim up.

Two on the deck I can be anywhere from 18-20L/100km driving like I do. Holding to the speed limit where it never goes over 100 I can get just over 600km and that’s 100L of fuel so barely 17L/100 driving like a granny.

The 6.4 was 22-24. Big deal. Like I said a couple more L/100km for some guys it just isn’t worth the price to get into a diesel if there are no deals to be had. Winter diesel prices suck. Sure more energy per litre but, $100 + for two fuel filters once a year, more expensive oil changes if you do them at the same intervals as the gas truck, so comparing 18-20 to 20-24 on the high side isn’t that unimaginable.

These claims of some of these diesel owners are bs on their mileage. Stock trucks will never see these claims. Never do they show proof or their life fuel average. One time they get 800km on a tank with a tail wind being drafted by a semi and that’s the example they always use.

What year is your truck? My 16 will get 800 empty highway km any day. On a really good day I have hit 904, but it's not often I'll see north of 850. And that's not on the EVIC, that's distance travelled between fillup. I keep a log for tax purposes. Last trip to Valemount I averaged 15.9 l/100 with sleds on deck. My lifetime average is a bit skewed due to lots of idling, and heavy towing, but it's currently sitting at 20.4l/100km with 125000km on the clock. But that's with ~650 hours of idling, and ~35,000km running over 22,000lbs gcvw, not to mention ~15,000km with two sleds on deck.