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Towing with new 6.4L

Bigv said:
The funny thing is I get 7 mpg on my diesel. That’s what the hemi got. LOL that is going to sturgis. Started with a Ford twin turbo, then the hemi 2500, now the diesel 3500
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I've said that before. Towed my 31' travel trailer with my 2500 6.4 and my neighbors F350 6.7, got 8-10 MPG with both vehicles doing the same trip. Honestly there was no difference in "ease" between trucks. Might have been different if it was a mountain trip, but this was a coastal trip on mostly flat ground.
 
I had a 2014 2500 with the 6.4/6spd and it really was a dog unless you rallied the chit out of the motor. I sold it and got a 1500 EcoDiesel with the ZF8 and that motor/transmission towed so much better that the 6.4. I am sure it was almost all in the ZF. If I had the ZF with the 6.4 I'd probably still be driving it. The 1500 ended up just being too small for the loads I tow so I stayed with the oil burner and went to the 3500 this time. Very happy, but I'd have a lot more money in the bank if that ZF had been on the 6.4.... :)
 
MegaRed said:
I had a 2014 2500 with the 6.4/6spd and it really was a dog unless you rallied the chit out of the motor. I sold it and got a 1500 EcoDiesel with the ZF8 and that motor/transmission towed so much better that the 6.4. I am sure it was almost all in the ZF. If I had the ZF with the 6.4 I'd probably still be driving it. The 1500 ended up just being too small for the loads I tow so I stayed with the oil burner and went to the 3500 this time. Very happy, but I'd have a lot more money in the bank if that ZF had been on the 6.4.... :)
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I totally agree, the modern transmissions are a game changer. The move from 4 speed to 6 speed was big, and from 6 speed to 8 speed IMO was an even bigger improvement with the gas engines. I haven't driven a 10 speed yet, part of me wonders if that's a step too far, but then again maybe it's even better.
 
Dave01 said:
I totally agree, the modern transmissions are a game changer. The move from 4 speed to 6 speed was big, and from 6 speed to 8 speed IMO was an even bigger improvement with the gas engines. I haven't driven a 10 speed yet, part of me wonders if that's a step too far, but then again maybe it's even better.
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It being a ZF is a huge improvement in and of itself.

The GM/Ford/Allison 10 speed has had a lot of issues.
 
We have both a 2016 Ram 2500 Power Wagon 6.4L and a 2024 Ram 3500 4x4 HO Cummins SRW within the Rockies. Both 6 speeds and I'll manually select whatever the best gear is on our home's steep downgrades to hold it back at or under the posted speed limit. Throw in a few more gears on the transmissions and from experience of going from 3 to 4 to 5 to 6 speed pickup trucks it still requires some magnitude of continuously stabbing of the brakes to slow down on the long sections with 8% to up to 10% gradients. Maybe having 8 to 10 speeds help a bit, but the exhaust brake on the Cummins can't be understated versus our gas. Still have to tap the brakes with a load and towing with it activated, but it is so much less of a concern with the additional engine braking. It's a 6K foot drop in just over 20 miles. Love the exhaust braking.
 
The little woman and I just got home yesterday from a 2,200 mile trip pulling our 24ft enclosed cargo trailer. We had our street bikes and a few other things in the trailer. Gross combined weight was 13,000lbs.
The trip was from southern Oregon to southern Utah and back. Very mountainous terrain most of the way.
Our truck is a 2021 3500 4x4 crew cab with the 6.4 gasser. It pulled the trailer great. For the most part, I kept the cruise set at 65mph most of the time. The dash said that we averaged 11.5mpg, but my hand calculations said 10.5.
I am happy with it.
 
just James said:
The little woman and I just got home yesterday from a 2,200 mile trip pulling our 24ft enclosed cargo trailer. We had our street bikes and a few other things in the trailer. Gross combined weight was 13,000lbs.
The trip was from southern Oregon to southern Utah and back. Very mountainous terrain most of the way.
Our truck is a 2021 3500 4x4 crew cab with the 6.4 gasser. It pulled the trailer great. For the most part, I kept the cruise set at 65mph most of the time. The dash said that we averaged 11.5mpg, but my hand calculations said 10.5.
I am happy with it.
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10.5 is good! I would have guessed lower, I tow an 8000 lb. car hauler type trailer and my mileage is definitely lower than that. The 1 mpg variance (dash always higher) is about what I've seen, I only hand calculated a few times, really don't care all that much.
 
What's weird is that I have a Fiat 500 that I commute to work in, and the mileage that it displays is absolutely spot on with hand calculations.
 
just James said:
What's weird is that I have a Fiat 500 that I commute to work in, and the mileage that it displays is absolutely spot on with hand calculations.
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Let's just say I've never had a dash indicator that read lower than actual. I don't know that it's outright deception, I think they just err on the side of being optimistic, plus tire diameter as they wear impacts the numbers. Though 11.5 indicated vs. 10.5 actual is 9.5% variance, you'd think they could get closer than that.
 
just James said:
The little woman and I just got home yesterday from a 2,200 mile trip pulling our 24ft enclosed cargo trailer. We had our street bikes and a few other things in the trailer. Gross combined weight was 13,000lbs.
The trip was from southern Oregon to southern Utah and back. Very mountainous terrain most of the way.
Our truck is a 2021 3500 4x4 crew cab with the 6.4 gasser. It pulled the trailer great. For the most part, I kept the cruise set at 65mph most of the time. The dash said that we averaged 11.5mpg, but my hand calculations said 10.5.
I am happy with it.
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I towed this last week and coming down I26 from NC into SC with my cruise set to 55 mph (the speed limit) and the truck was able to maintain 55 all the way down the 6% grade without using the brakes. However, the 6.4 was turning 5k RPMs to hold it back. The total weight was only 12,440 pounds, so not heavy.

Was yours able maintain speed going down hills without braking?
 

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dieselscout80 said:
I towed this last week and coming down I26 from NC into SC with my cruise set to 55 mph (the speed limit) and the truck was able to maintain 55 all the way down the 6% grade without using the brakes. However, the 6.4 was turning 5k RPMs to hold it back. The total weight was only 12,440 pounds, so not heavy.

Was yours able maintain speed going down hills without braking?
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I've no problems maintaining speed going up or down grades in W. NC, TN, upstate SC and W. VA. Yeah, it sings at 4-5k RPM's, but that's where V8's make their power. It's not some new concept, and they're not a diesel. Won't hurt the hemi one bit.
 
dieselscout80 said:
I towed this last week and coming down I26 from NC into SC with my cruise set to 55 mph (the speed limit) and the truck was able to maintain 55 all the way down the 6% grade without using the brakes. However, the 6.4 was turning 5k RPMs to hold it back. The total weight was only 12,440 pounds, so not heavy.

Was yours able maintain speed going down hills without braking?
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I had to use the brakes occasionally, but not what I would call excessively.
Maybe it is fine, but I can't stand the sound of the engine turning more than about 4,200rpm. At times, I would turn the cruise off when descending hills to keep the transmission from downshifting further than I wanted.
 
just James said:
I had to use the brakes occasionally, but not what I would call excessively.
Maybe it is fine, but I can't stand the sound of the engine turning more than about 4,200rpm. At times, I would turn the cruise off when descending hills to keep the transmission from downshifting further than I wanted.
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It’s definitely fine. These engines are made for this.
 
Asking for opinions: when you tow “smaller” trailers around 4,000 lbs or less, do you use Tow/Haul? In hilly terrain or when I want more engine braking I definitely turn it on, but I’ve noticed on absolutely flat roads when towing my smaller trailers in Tow/Haul the truck usually won’t go into 8th gear with the cruise set at 65. Turning off Tow/Haul in that situation she’ll immediately shift to 8th, and even engage “ECO” occasionally too. I’ll go from 9-10mpg to 12-13.

I’ve looked online and there’s no set number I can find when Tow/Haul use is mandatory.
 
copcarguy said:
Asking for opinions: when you tow “smaller” trailers around 4,000 lbs or less, do you use Tow/Haul? In hilly terrain or when I want more engine braking I definitely turn it on, but I’ve noticed on absolutely flat roads when towing my smaller trailers in Tow/Haul the truck usually won’t go into 8th gear with the cruise set at 65. Turning off Tow/Haul in that situation she’ll immediately shift to 8th, and even engage “ECO” occasionally too. I’ll go from 9-10mpg to 12-13.

I’ve looked online and there’s no set number I can find when Tow/Haul use is mandatory.
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Towing my trailer empty I leave tow/haul off. Like you i noticed about a 20% decrease in MPG just by having it in tow/haul.

That said with it loaded up it then weighs about 14,15K and I think tow/haul is awesome. It makes it stay in lower gears longer, reduces shifting and makes down shifting more aggressive. By that i mean if you have the cruise control set and go down a hill it will continue to down shift until it is maintaining speed within 5 mph of set speed or the engine is spinning around 5-5,400 rpm.

It is no Jake brake by any means but even if you need to apply the brakes to maintain speed think about how much heat is not going in to your brakes.
 
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