Regretting ordering 3.92 on my 22 Ram Ecodiesel and almost debating paying to downgrade to 3.21

aj_g · Jul 13, 2022

BossHogg said:
If you do the math on axle ratios and transmission output ratios you get a clearer picture. Back when RAM offered a 6-speed tranny with a 3:92 axle ratio and then began offering the new 8-speed with a 3:21 axel ratio the RAM forums went nuts. The math proved the 8-speed with a 3:21 axle ratio had lower gearing off the line than the 6-speed transmission with a 3:92 axle ratio. Lacking critical thought, the forums were not happy.

There is no shortage of opinion base justification but in usage cases, axle ratio decisions should be made on need. I can see that if one is going to be towing in the upper ranges of the vehicle's capacity and in areas that will cause a high amount of stop-and-go driving, then a 3:92 would be a better choice offering less stress on the drive line.

There is also the case for the age group that likes "jackrabbit" launches and/or traffic cowboying where a 3:92 will promote their desires.

Then there are drivers like me, older, living in a rural area, driving typical at speeds 50 MPH or more, minimal stop and go, and occasionally towing less than 7K pounds, 3:21s. The devil is always in the details which are typically not presented in opinion based posts.

Before I bought my 2022 ECO I had a 2013 HEMI RAM 1500, drove in the same areas as I now do, towed the same loads, and that 2013 also had a 3:21 axle ratio. I much prefer the ECODiesel as a daily driver and also for towing my lighter loads.

Since one's driving style is the major contributor to the vehicle's achieved MPG, it is difficult to compare the same vehicle with two different drivers, this is most obvious when reading forums and seeing what is posted for MPGs.

For your case, I say leave your axle ratios alone. In my 3:21 ECO, driving at 75 MPH, my engine is spinning at 1,650 RPMs and I'm realizing anywhere between 32.6 and 34.2 MPG on the open flat roadways. I've never driven the same vehicle with 3:92s so I can't compare the MPGs but I would think that spinning your engine 350 RPM faster than mine isn't going to make much difference in MPG. Likely your driving style and the cetane level in California fuel are going to be the major contributors to your mileage.

Wow 32.6-34.2 wtf lol. What state are you in?
I did these tests on cruise control on flat ground with little to no braking and refrained from flooring the accelerator - so almost optimal conditions.
It wasnt very windy either.

Rlaf75 · Jul 13, 2022

aj_g said:
You make a lot of sense, ty for the suggestion.
Im a bit mentally stuck on the mpg because my old 2017 Ram 1500 used to get 25-26mpg while driving as I normally do

And I completely understand especially with the price of gas and fuel now. Like I said previously, there's a lot of variables to take into consideration when dealing with mpg. You can have two identical vehicles and get two very different results.

aj_g · Jul 13, 2022

crazykid1994 said:
What is your fuel cost difference going to equate to in time to make switching the gears actually beneficial? How long before you turn profit. And these trucks turn into brick walls above 70mph anyways so the aerodynamics and drag will greatly reduce your fuel efficiency above 70mph anyways.

I did some rough calculations on this assuming 70mph is the advertised 29mpg and at $6.00 per gallon diesel.
If I drive as I normally do, ~$930 extra spent on diesel per every 10k miles along, you're gonna laugh at me for pointing it out but, an extra 17 hours per 10k miles lol.

So assuming total cost is ~5k to go to 3.21, it would take me a 50k+ miles to recuperate the cost. I'll probably be ready to trade it in for a different ram at that point before I can even get to 50k+ miles as it will be in some years lol.

Valid point as well, thank you.

aj_g · Jul 13, 2022

ramffml said:
Since when is the 3.21 considered a "downgrade"? That's the kind of mindset that leads to problems like this. There are pros and cons to both gears.

The short answer is you did get the wrong gear ratio for your usage, but you'd have to calculate how much you save per tank in order to justify a conversion. Your best fuel savings will come driving at 60 mph, the EPA rates their trucks at about 55 IIRC, no way you're getting close to those ratings at 70+.

This forum hates the 3.21, but it's the better choice for most people based on what you see the average person doing with a truck. Especially with the diesel's low end torque, I can't imagine why you'd want the 3.92. You don't tow much, but the dirty secret is that both gears will tow just as much in the city and on the freeway, the 3.92 only gets you off the line slightly quicker due to having a deeper first gear but once you shift out of first and you're on the freeway, both trucks have the same gear ratios available for usage.

Sorry the only reason I mentioned "downgrade" was just that Im going for a numerically lower gear ratio.
The reason I created this post in the first place is that I was considering it an "upgrade" to my current situation

aj_g · Jul 13, 2022

Zoe Saldana said:
Let's see the math for you to break even on the $2,750 + labor cost.

Just posted in another reply above if you want to take a glance

aj_g · Jul 13, 2022

GTyankee said:
I am lucky enough to have the Eco-diesel with 3.55s & LSD

I will likely never tow, but my bed usually has 700 pounds in it

a 3.21 was my first choice, but it was not available

at the traffic light, the grandma in the other lane beats me off the Line. I build up to highway speed slowly most times, it depends on the speed of the rest of the traffic.

California has a drag strip at every On Ramp during high traffic hours, the Ramps are Metered.
The Stop Bar at the Ramps traffic light is the Line, it changes to Green & you are expected to Merge with Traffic at speed, hell, you can do 100 mph in a quarter mile & not get ticketed

That is not me any more, i drive 73 MPH on the Highway that is posted 70 MPH

I know that i save fuel & most times i get to the next town at the same Time as those that went racing by me.

Let your Ram get about 4 to 5,000 miles on it, you may find the your MPG improves, like with the gas engines

Cheers, thank you

BossHogg · Jul 13, 2022

aj_g said:
Wow 32.6-34.2 wtf lol. What state are you in?

Michigan. 2022 ED with the GDE engine and transmission tune.

aj_g · Jul 13, 2022

BossHogg said:
Michigan. 2022 ED with the GDE engine and transmission tune.

Sorry I'm not familiar with "GDE", could you elaborate please? Also exactly are you referring to by transmission tune? Bit of a noob here, thank you

Tony1945 · Jul 13, 2022

aj_g said:
Hi, I had ordered my RAM with 3.92 ratio as I only seemed to come across the good articles at that time in which I learned that it will have a higher resale value in the future, better for towing, etc. I did see some mention of a negligible difference in mpg but thought nothing of it as the sticker did not update on the MPG at all after I selected 3.92. I had even picked up the bigger diesel tank because I wanted to be able to go on long trips while dreaming about the 29mpg thats advertised lmao.

I live in California, almost everyone and their mother drives 80mph here on the highways and most drive even faster. I live in a fairly rural area, I have to drive on the highways a fair bit in order to get most things.
In my first few weeks of testing, here's what I've noticed for mpg
80mph = 2200 rpm and ~20mpg
75mph = Just over 2000 rpm and ~24mpg
70mph = I dont remember the exact rpm but its 27+mpg

I did reach out to the service department at my local dealer and was told $2,750 + labor in order to switch to a 3.21 (guy sent me a detailed parts list as for the breakdown) and I'm following up with them now to see how much labor that would be.

In terms of switching over
Pros:
For the most part I can drive as I normally do and not have to worry about being inefficient in terms of diesel
Would be saving time as well as I'd be driving at 80mph instead of 70/75

Cons:
The upfront cost of course
Potential resale value in the future may be impacted but I dont like switching cars very often
Towing impact, I dont tow much now but it was just futureproofing

You may be calling me crazy but this is bothering me so much, like how did I look into every little detail and end up making this big of a mistake. Also, I am under the assumption that going to 3.21 will give me lower RPM's at 80mph, please correct me if I'm wrong.

It needs to break in 7k +

crash68 · Jul 13, 2022

aj_g said:
Sorry I'm not familiar with "GDE", could you elaborate please? Also exactly are you referring to by transmission tune? Bit of a noob here, thank you

Green Diesel Engineering, they have a 49 state legal tune that optimizes the EcoDiesel engine along with adding horsepower, torque and fuel economy and it also includes tuning the transmission that works with the engine tune.
Unfortunately since CARB decides to not accept federal certified testing and requires their own of which the manufacturer has to pay for. The tune isn't available for sale in California.

aj_g · Jul 14, 2022

crash68 said:
Green Diesel Engineering, they have a 49 state legal tune that optimizes the EcoDiesel engine along with adding horsepower, torque and fuel economy and it also includes tuning the transmission that works with the engine tune.
Unfortunately since CARB decides to not accept federal certified testing and requires their own of which the manufacturer has to pay for. The tune isn't available for sale in California.

Wow, talk about another instance of "******* California".
I'm assuming its not as simple as getting it done from another state. Tbh how would California even know, I guess when it comes down to smog tests etc down the road?

GTyankee · Jul 14, 2022

yeah & our dear governor is running for the top position
he hates oil drilling too

crash68 · Jul 14, 2022

aj_g said:
Tbh how would California even know, I guess when it comes down to smog tests etc down the road?

GDE verifies where the vehicle is registered at for purchasing the tune. The tune is tied to the VIN number of the vehicle.
The tune itself will most likely pass any of the smog test and/or inspections. It sounds like the testing to get an EO number from CARB isn't cheap.

BossHogg · Jul 14, 2022

aj_g said:
Sorry I'm not familiar with "GDE", could you elaborate please? Also exactly are you referring to by transmission tune? Bit of a noob here, thank you

California is a nice place for the weather but in some places, living shoulder to shoulder just isn't my idea of life. And the rules. regulations. loss of rights, and the number of wack-os, wow. My oldest and youngest sons both lived in California, the youngest in Riverside, and the oldest in Lake Forest. Both have left for Arizona in the past year. The cost of living and the cost of property versus the wages forced them to leave. I may have to put up with snow and cold for a few months but living rural, on 20 acres, and surrounded by the Great Lakes, I'll never leave.

I've spent my career in automotive electronics and software engineering for Ford and GM plus a handful of suppliers. My oldest stepson is also in the powertrain side of automotive and for a while, worked on the ECODiesel program at Chrysler. When I picked up my new ED, I knew the factory tune just wasn't for me so I drove over to GDE and had both the transmission tune and the engine tune installed. I put a link to what their tunes are about for the ED.

My son knew the calibration engineers at GDE, and at times, even seeming hudge, automotive can be small. These guys, all calibration engineers, know what they are doing. They have been calibrating powertrains and drivelines for years. The calibrations are outstanding while meeting emissions, returning customer satisfaction to the driving experience, increasing performance, increasing MPGs, reducing the regenerations, making good use of the low-pressure EGR, better shift logic, etc.

CARB is a pain and eventually will regulate themselves out of existence.

RAM Jeep EcoDiesel Street Legal Engine & Trans Tune - GDE

Ram Jeep EcoDiesel Compliant Engine & Trans Tune Combo. This is the only street legal RAM Jeep EcoDiesel Engine Tuning product available.

greendieselengineering.com

Paladin308 · Jul 14, 2022

aj_g said:
Hi, I had ordered my RAM with 3.92 ratio as I only seemed to come across the good articles at that time in which I learned that it will have a higher resale value in the future, better for towing, etc. I did see some mention of a negligible difference in mpg but thought nothing of it as the sticker did not update on the MPG at all after I selected 3.92. I had even picked up the bigger diesel tank because I wanted to be able to go on long trips while dreaming about the 29mpg thats advertised lmao.

I live in California, almost everyone and their mother drives 80mph here on the highways and most drive even faster. I live in a fairly rural area, I have to drive on the highways a fair bit in order to get most things.
In my first few weeks of testing, here's what I've noticed for mpg
80mph = 2200 rpm and ~20mpg
75mph = Just over 2000 rpm and ~24mpg
70mph = I dont remember the exact rpm but its 27+mpg

I did reach out to the service department at my local dealer and was told $2,750 + labor in order to switch to a 3.21 (guy sent me a detailed parts list as for the breakdown) and I'm following up with them now to see how much labor that would be.

In terms of switching over
Pros:
For the most part I can drive as I normally do and not have to worry about being inefficient in terms of diesel
Would be saving time as well as I'd be driving at 80mph instead of 70/75

Cons:
The upfront cost of course
Potential resale value in the future may be impacted but I dont like switching cars very often
Towing impact, I dont tow much now but it was just futureproofing

You may be calling me crazy but this is bothering me so much, like how did I look into every little detail and end up making this big of a mistake. Also, I am under the assumption that going to 3.21 will give me lower RPM's at 80mph, please correct me if I'm wrong.

I have a 2022 Limited with 3.0eco diesel. 3.92 rear axle. I get an average of 28mpg. That's combined freeway, highway, and city driving. Granted, I don't drive 80, usually 77 on the freeway and 59 on the highway. RPM under 2,000.

CaptQ · Jul 14, 2022

aj_g said:
“I did reach out to the service department at my local dealer and was told $2,750 + labor in order to switch to a 3.21 (guy sent me a detailed parts list as for the breakdown) and I'm following up with them now to see how much labor that would be.”

CaptQ · Jul 14, 2022

Holy sh** (cow). I’ve done a lot of axle overhauls, gear swaps, mods and repairs. That’s probably one of the highest quotes I’ve seen for a gear swap. Take it to a driveline specialist and get it done right. $2750 total is a good price for a 4x4. Not including labor? It’s all labor.

Narg · Jul 14, 2022

I would love if RAM had a 3.55 in all engines. GM has the middle ratio in most of theirs, as does Ford.

MikeinSonoma · Jul 14, 2022

Wahrsuul said:
Considering I drive 60-65 around town and 70 on the highway, I'd be pretty tickled with 27+mpg instead of the 17-20 I get now.

With my 2021 Rebel V6 etorque, I’d be tickled with 20mpg. If I could drive 65 on a flat Road with no stops for a whole tank (33g) I might get 20. Sticker said 19 to 24, It usually lands from 16 to 18.

Panduh · Jul 14, 2022

I hope you agree with the consensus that it's really not worth the $$ to switch ratios. You WILL have a higher resale value with the 3:92 as it has a considerably higher towing ability. I looked long and hard for a good used 1500 hemi with the 3:92 and absolutely love it, both in everyday driving and esp. when towing my 6000 lb. camper.

Regretting ordering 3.92 on my 22 Ram Ecodiesel and almost debating paying to downgrade to 3.21

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