RAM 3500 with HO 6.7L Cummins SRW

[Showme_5vr]

Just discovered that the new RAM we ordered has been built and is waiting to ship. The 2015 RAM 2500 with the regular 6.7L Cummins that we have now will get around 20-21 miles per gallon when running empty on a trip. Does anyone have experience with the HO on fuel mileage? Both trucks have the 3.73 rear end.
Thanks

[Cummins12V98]

Larry stays quite busy, he is a Wood Magician.

[Grit_dog]

larry barnhart wrote:
for our combined 22,900 lbs. I didn't have any issue with a 5 sp Allison Duramax awesome truck. Not saying it would be great for a much bigger fifth but I was happy. No issues going down mountians. Now I get to look at it everyday waiting for me to get some fresh air. chevman

😞
I feel for ya Larry. I know what you’re going thru. Stay strong!

[larry_barnhart]

for our combined 22,900 lbs. I didn't have any issue with a 5 sp Allison Duramax awesome truck. Not saying it would be great for a much bigger fifth but I was happy. No issues going down mountians. Now I get to look at it everyday waiting for me to get some fresh air. chevman

[Cummins12V98]

Grit dog wrote:

Me Again wrote:
My F-150 has a 10 speed and it spends a lot of time shifting gears, sometimes skipping a gear. I am sure that 7 or 8 would have been just fine behind the 2.7L ecoboost that has a broad torque curve down low. It is said that it is snappier and more fun to drive than the 3.5L ecoboost.

I agree. 8 or 9 forward gears is the practical max/ideal gears needed. The 10 speed like you have only has about 150 rpm’s diff between 9 and 10. That’s one gear split not needed.

I don't need "SPLITS". :B

[Grit_dog]

Me Again wrote:
My F-150 has a 10 speed and it spends a lot of time shifting gears, sometimes skipping a gear. I am sure that 7 or 8 would have been just fine behind the 2.7L ecoboost that has a broad torque curve down low. It is said that it is snappier and more fun to drive than the 3.5L ecoboost.

I agree. 8 or 9 forward gears is the practical max/ideal gears needed. The 10 speed like you have only has about 150 rpm’s diff between 9 and 10. That’s one gear split not needed.

[Me_Again]

My F-150 has a 10 speed and it spends a lot of time shifting gears, sometimes skipping a gear. I am sure that 7 or 8 would have been just fine behind the 2.7L ecoboost that has a broad torque curve down low. It is said that it is snappier and more fun to drive than the 3.5L ecoboost.

[Grit_dog]

Cummins12V98 wrote:

Grit dog wrote:
And yes, a new 3.73 HO will not get as good of empty cruising fuel mileage as a 3.42 standard Cummins.
But if they’re both srw trucks, the difference should not be huge. Maybe a couple mpgs.

Also, I’d wait for a 2024 model…..can’t say why, but anyone halfway well read about Ram’s current and future transmission options will understand.
I’ll throw out a clue. 12V says this will not be a worthwhile change….lol.

This transmission change has been "going to happen" for several years. We will see what if anything changes in 2024. So far RAM has not caved to the "more is better" mentality.

Icbw, but will have to wait and see. That’s all I’ll say aboot that.
But “Ram has not caved to the more gears is better, is laughable, and nothing more than your own personal theory and undying love for the Aisin trans.
They were late to the table with Hd gassers with >6 speeds as well. And the 66rfe that was replaced by the 8HP was far too long in coming.
However, who lead the US (and Jap truck) market in introducing the 8HP pretty much, no, completely, across their rwd/4wd platforms from cars to suvs to light duty pickups in 2015?

Yup it was Chrysler. Not Ford, GM, Yoda or Nissan.
Ram didn’t “cave in” even though they were real world testing the ZF Powerline back in like 2018? Iirc.
Your theory is simply that of unfounded opinion vs what really happened at FCA/Stellantis over the last 5 years or so. Ram has been long overdue for an upgrade in this department.

Maybe I’ll eat my words but I bet you’ll see your beloved AS69rc and the old maligned 68rfe bite the dust for good here real soon! Hopefully….

[Cummins12V98]

Me Again said: "I still think they got rid of the 3.42's as a concession to the 68 RFE's taller 1st and 2nd gears."


100% agree! Take those gears and put them behind the AISIN with it's lower starting gears and you have a GREAT combo for towing and running Bobtail.

To order my truck again I would skip the 4.10's and order the 3,42's. I would tow at 60 at 1,750 rpm's in 5th the same turns as 4.10's in 6th. YES even at my 35k combined and West Coast Towing!!!

[Cummins12V98]

Grit dog wrote:
And yes, a new 3.73 HO will not get as good of empty cruising fuel mileage as a 3.42 standard Cummins.
But if they’re both srw trucks, the difference should not be huge. Maybe a couple mpgs.

Also, I’d wait for a 2024 model…..can’t say why, but anyone halfway well read about Ram’s current and future transmission options will understand.
I’ll throw out a clue. 12V says this will not be a worthwhile change….lol.

This transmission change has been "going to happen" for several years. We will see what if anything changes in 2024. So far RAM has not caved to the "more is better" mentality.

[Me_Again]

If I kept my 2015 3500 4x4 HO SBW SB Laramie at 70 MPH it would break the 20 mpg barrier easily. Towing at 24,500 lbs combined with tall 5th wheel netted 10.5-11 mpg. Did I ever say, "I loved my 3.42 gears"? 80 MPH at 1750 rpms.

I still think they got rid of the 3.42's as a concession to the 68 RFE's taller 1st and 2nd gears.

[Grit_dog]

Walaby wrote:
I have a 2017 Ram 3500, 6.7HO and Aisen Trans.

I had a 2014 Ram 2590 6.7 as well prior to the 3500.

3500 gets probably 1.5-2MPG less than the 2500 when not towing.

Towing it's about the same.

Mike

Sounds spot on with what would be expected.

[Walaby]

I have a 2017 Ram 3500, 6.7HO and Aisen Trans.

I had a 2014 Ram 2590 6.7 as well prior to the 3500.

3500 gets probably 1.5-2MPG less than the 2500 when not towing.

Towing it's about the same.

Mike

[Grit_dog]

And yes, a new 3.73 HO will not get as good of empty cruising fuel mileage as a 3.42 standard Cummins.
But if they’re both srw trucks, the difference should not be huge. Maybe a couple mpgs.

Also, I’d wait for a 2024 model…..can’t say why, but anyone halfway well read about Ram’s current and future transmission options will understand.
I’ll throw out a clue. 12V says this will not be a worthwhile change….lol.

[Grit_dog]

deltabravo wrote:
I've always wondered what the major differences are between the HO and Standard 6.7 Cummins. I have no clue because I've owned GM trucks and I don't know anyone that owns a RAM.

cummins2014 wrote:
. Never gave mileage much thought , truck was not bought for economy . Mileage towing as said is probably going to be about the same.

Best answer yet.
With that said, I sure wish my old school Duramax got better mileage, but I can't Justify the cost to replace it. It only has 75k miles on it.

You can get better mileage easily, but it’ll cost you a couple grand to do so (including exhaust). Delete that thing while you still can. The LMMs were the worst for fuel economy of all generations of that engine due to the early Tier IV emissions requirements and prior to the introduction of DEF into emissions technology. It’s that pesky 9th injector that is using up your extra diesel.