Towing with 6.4 hemi

[Wild one]

To me a Hemi screaming at 5,000 rpm reminds me of the old loud smelly Detroit 318 Diesel aka 8V-71, when I first heard one on the hwy I wondered about how soon before parts would fly out of the block, not liking to hear high rpms guess that happens when you been hanging around the Cummins for years

Also famous for running away and screaming their guts out till they turned into a grenade,if you didn't get to the air intake fast enough to choke them to death

 

[HEMIMANN]

To me a Hemi screaming at 5,000 rpm reminds me of the old loud smelly Detroit 318 Diesel aka 8V-71, when I first heard one on the hwy I wondered about how soon before parts would fly out of the block, not liking to hear high rpms guess that happens when you been hanging around the Cummins for years

I loved those things in the city buses! The roar of power!!! lol

 

[Replacement]

I have a '25 6.4 with 4.10 and pull a 6k TT. So far no problems, gets the trailer moving just fine and if i really put my foot into she pulls pretty hard. Absolutely zero complaints. The 6.4 is thirsty and is widely known.

 

[Replacement]

The past weekend we took our trailer to the mountains. About 300miles total.

Needed 4th gear a couple times on some of the hills (60-65mph)

Highest trans temp 165
Highest oil temp 255
Highest elevation across the trip 6k
Hand calc mpg 9.5

No complaints.

 

[HEMIMANN]

The past weekend we took our trailer to the mountains. About 300miles total.

Needed 4th gear a couple times on some of the hills (60-65mph)

Highest trans temp 165
Highest oil temp 255
Highest elevation across the trip 6k
Hand calc mpg 9.5

No complaints.

255F oil seems hot. Mine doesn't get above 230F.

What was the ambient temp? Do you have the ATF cooler bypass installed?

 

[Replacement]

255F oil seems hot. Mine doesn't get above 230F.

What was the ambient temp? Do you have the ATF cooler bypass installed?

Ambient was 80F.
Haven't done anything with the bypass, truck is stock.

I thought it was hot previously but seems fairly common among the forums and everyone says they run hot so i haven't been concerned.

On the flats or mild hills 230-235 is where it sits only the longer or high rpm hills cause the rise.

Funny enough I'll be making the same trip again this weekend although a bit lighter load 500-750lbs less anyways.

 

[ramffml]

Yeah the hemi gets to sing... guys in mustangs/camaros pay extra to hear that v8 at high rpms instead of the v6 or 4 bangers, but when it comes time to tow it seems people don't want to hear it. I don't get it

Anyway, the alternative is a huge honking diesel. They are torque monsters and a pleasure to tow with, and everytime I get the itch I see a story like this; brand new cummins with < 2000 miles requiring a $15k emissions repair. Warranty covered it... this time. What about later on?

2026 Ram 3500 DPF Failure & Limp Mode… Our Honest 7-Month Review

Our brand new 2026 Ram 3500 Mega Cab 4x4 Laramie went into limp mode at only 1,600 miles after a major DEF system failure, resulting in a massive warranty re...

www.youtube.com

 

[2003F350]

Yeah the hemi gets to sing... guys in mustangs/camaros pay extra to hear that v8 at high rpms instead of the v6 or 4 bangers, but when it comes time to tow it seems people don't want to hear it. I don't get it

Anyway, the alternative is a huge honking diesel. They are torque monsters and a pleasure to tow with, and everytime I get the itch I see a story like this; brand new cummins with < 2000 miles requiring a $15k emissions repair. Warranty covered it... this time. What about later on?

2026 Ram 3500 DPF Failure & Limp Mode… Our Honest 7-Month Review

Our brand new 2026 Ram 3500 Mega Cab 4x4 Laramie went into limp mode at only 1,600 miles after a major DEF system failure, resulting in a massive warranty re...

www.youtube.com

That story typically comes from guys who buy a diesel and then try to drive it around town and let it idle all the time. Modern aftertreatment systems don't like that. Those systems need to be run to be kept clean.

Used to see the same complaint back when catalytic converters were starting to become mandatory in light-duty trucks. People who never had vehicle troubles before were suddenly seeing issues at 40-50k miles. Trouble was those miles were all in 4-5 mile trips, where the exhaust system never got to a high enough temp to burn everything off, and clogged up. You don't see (or hear) about that as much anymore, because gas engines are designed to run hotter, heat up faster, and get those catalytic converters hot enough to burn things off quickly.

I imagine you'll eventually see something similar in diesel trucks, once they have a system that will effectively collect NOx emissions. I honestly think they're getting close, with the 7th (CTD) or 9th (PSD) injector systems. Faster regens, and at least on the Ford (Dunno about the Rams yet) regens designed around a time/mileage instead of soot load will help keep those systems functioning better and longer.

 

[ramffml]

That story typically comes from guys who buy a diesel and then try to drive it around town and let it idle all the time.

Nope. Brand new truck, less than 2000 miles. The system just failed due to a bad sensor. Which is the point... you can drive the truck "wrong" and create problems, you can do everything right and still get problems, and the price of the problems is half the value of a replacement truck.

 

[Tulecreeper]

I have a 2500 I bought in 2023 with the 6.4 and 3.73 rear end and have hauled that much on several occasions with zero issues. Yes, it will rev up going uphill but that's what it's supposed to do. I use Tow/Haul mode when towing more than about 2k pounds and when going downhill I just drop the ERS to whatever gear feels right and keeps me at the safe speed I want and the truck does all the work.

Sound to me like your truck is doing what it's supposed to do.

 

[wrench78]

The truck has 24,000 miles on it. It has been serviced at the recommended intervals at a ram dealer. This last trip, I had the cruise control set at 65 and the engine was tacking around 4500 on a slight incline. It seemed like the engine was working way to hard for the driving conditions. I am definitely going to investigate the brakes on the camper to make sure they aren’t hanging up. Side note: this last trip was around 70 miles round trip and I used about 3/8 of a tank of gas.

To me, the 4k towing up hill sounds normal. That's about where mine likes to tow. Live in SEPA, and have towed all the mtns in PA, NY, and VA. No issues. The 6.4L is a very thirsty engine. Not much you can do about that. I average 8-9 mpg towing my 7k camper. Also, keep in mind, if you are in tow/haul mode, you won't see 8th gear.

 

[Dean2]

The Dodge V10 in my 96 2500 was a truly outsatnding motor for towing. It made its max torgue of 450 ft lbs at 2400 rpm and produced over 350 ft lbs just off idle and got to 400 ft lbs by 1900 rpm. No modern gasser does that but the new ones do get a bunch better gas mileage. My 6.4 is easily a 60% improvement in gas mileage, empty and 20% hauling.

 

[ramffml]

The Dodge V10 in my 96 2500 was a truly outsatnding motor for towing. It made its max torgue of 450 ft lbs at 2400 rpm and produced over 350 ft lbs just off idle and got to 400 ft lbs by 1900 rpm. No modern gasser does that but the new ones do get a bunch better gas mileage. My 6.4 is easily a 60% improvement in gas mileage, empty and 20% hauling.

The 7.3 has to be quite close though I'm sure, if not better in some ways. Somebody needs to do a direct head to head on those two!

 

[Tulecreeper]

To me, the 4k towing up hill sounds normal. That's about where mine likes to tow. Live in SEPA, and have towed all the mtns in PA, NY, and VA. No issues. The 6.4L is a very thirsty engine. Not much you can do about that. I average 8-9 mpg towing my 7k camper. Also, keep in mind, if you are in tow/haul mode, you won't see 8th gear.

Since so many people have said that, I tested that theory right after I got the truck in 2023. I put it in T/H mode and about the time I hit 65 MPH it went into 8th gear.

 

[joesstripclub]

Since so many people have said that, I tested that theory right after I got the truck in 2023. I put it in T/H mode and about the time I hit 65 MPH it went into 8th gear.

Tow haul seems to be a lot less noticeable in my 2500 vs my 2018 1500. The 1500 was real aggressive at down shifting when slowing and holding gears before upshifting. Maybe the 2500 is a bit smarter with it and can tell when you are towing and adjusts T/H parameters on the fly.

 

[HEMIMANN]

If you got the ZF8 trans, it doesnt need much shift change Iike the marginal RFE trans does.

 

[2003F350]

Since so many people have said that, I tested that theory right after I got the truck in 2023. I put it in T/H mode and about the time I hit 65 MPH it went into 8th gear.

Every vehicle I have owned with a 'tow/haul' mode DID go into top gear when in tow/haul, even when towing. My '03 F350 would go into 5th gear (6.0/5spd auto), my '04 F350 dually (same as '03), my '17 Wagon (6.4/6-spd), my '22 2500 CTD (6.7/6spd), and now my '25 F350 (6.7/10spd). Now granted, they wouldn't hit top gear at 55mph...but they ABSOLUTELY would/will on the expressway at 65+.

 

[ramffml]

The question is... why would you want OD while towing? I lock both 7/8 out in my truck.