Kindly help me choose between Standard and High Output Cummins

[gimmie11s]

Sure, the HO makes more power but unloaded the SO will be more responsive, get better MPG, and is faster 0-60. The SO has a higher compression ratio which will make the truck feel more responsive and net overall better fuel economy. Hook up a trailer and the HO will dominate the SO in terms of performance, it all boils down to how you will use your truck.

I have to disagree w/this. My 2016 SO cummins didn't have near the power my 2021 HO has. The 21 truck would absolutely waste the 2016 in a drag race -- the 21 is definitely "faster".

Further, the 2016 68rfe was just as, or more "clunky" than my Aisin trans. Now.... .perhaps the 19+ 68rfe trucks have better trans tuning than the 2016 I used to own.

Just another anecdote to consider from someone who's owned both.

 

[hdas]

Other forum members have said there is little to no difference in terms of responsiveness

Thanks. I think my perceptions will biased by the fact that I mostly drive 20+ year old cars that have almost no responsiveness. But for sure I will test drive both and compare. However, last weekend I was unable to find any 3500 to test drive within 1 hour of home.

 

[SpeyRam]

You should never ask these kinds of questions on a truck forum as you’ll never get a perfect answer! I’ve asked the same one but still ended up ordering one with the motor I wanted (just placed an HO order). The majority of us on this forum I suspect (although there are some for sure) don’t need or come close to the operating limits of an HO model. I know I won't ever haul bales of hay or use the thing as a daily work truck out on some oil fields but it'll be peace of mind nice to know I have the extra if I ever do need it. At least, that's my argument.

 

[hdas]

I saw your post about the Expo rear carrier on Expo. I recently purchased a front bumper from them, and I'll say that the product seems well enough built but there are some minor issues, and their shipping/CS is poor at best. I mean to write up an article about my experience and share it on the forum. I started to document my experience in this thread, and while it's finally "resolved", I'd say that my experience is far less than ideal.

Thank you for documenting your experience. Definitely a warning sign. Browsing the landscape, it seems that the RigdSupply Swing could be the only game in town.

if you're willing to spend the additional coin on a built trans.

My main apprehension is not the coin, but the expertise. Sadly I've lived my life immersed in computers and finance and neglected mechanical knowledge that could have come handy in this project. So it's always a steep learning curve to learn enough to trust an aftermarket vendor. For better or for worse, this is one of the reasons I decided to go with AEV.

Everyone has thoughts on payload/axle ratings and all that, so I'm happy to deeper dive my thoughts if you're interested, but that's a choice you'll want to make.

Even though I'm set on sticking to payload numbers as non sensical as it might sound to some people. I would love to hear a knowledgeable contrarian perspective.

I think you could go either 2500 or 3500 depending on how you feel about the rear suspension.

The esteemed @ramblinChet seems to be cruising the backroads fine in his 3500. But it would be nice to have a thread going comparing both experiences, specifically for heavy offroad with the load of campers. But yes, logic tells us the 2500 will be ahead in the rear articulation department, with higher constrains in terms of payload

 

[gpattikjr]

I got the HO specifically for the trans. I avg 17-22 mpg. Learn to roll into the throttle.

 

[AH64ID]

... with a better gear ratio for what you want than the Aisin

Wouldn't the 16% lower 1st gear and 9% lower 2nd gear of the Aisin be the better gear ratio for slow speed driving and overlanding?

The 68RFE does have a slight advantage in 3rd and 5th, but the torque of the HO still has more available at the wheels at those speeds.

 

[hdas]

Wouldn't the 16% lower 1st gear and 9% lower 2nd gear of the Aisin be the better gear ratio for slow speed driving and overlanding?

The 68RFE does have a slight advantage in 3rd and 5th, but the torque of the HO still has more available at the wheels at those speeds.

This has been my thought all along. The sad thing is that I don't think any dealer would let me test drive the car to a steep, rocky and loose hill nearby.

 

[UglyViking]

Thank you for documenting your experience. Definitely a warning sign. Browsing the landscape, it seems that the RigdSupply Swing could be the only game in town.

The Rigd swing is def a durable unit from everything I've read. Biggest downside being the additional length hurting departure angle, that may or may not be a concern depending on the types of trails you like to hit. It's probably a non-issue for the vast majority of overlanders.

My main apprehension is not the coin, but the expertise. Sadly I've lived my life immersed in computers and finance and neglected mechanical knowledge that could have come handy in this project. So it's always a steep learning curve to learn enough to trust an aftermarket vendor. For better or for worse, this is one of the reasons I decided to go with AEV.

For a trans swap, if you're not mechanically inclined, I'd def recommend a shop. As far as AEV goes, they make some excellent products, for sure, but their suspension is not what I'd consider an ideal solution. I know that @ramblinChet and I have a bit of a playful banter back and forth on this, as he is a strong supporter of AEVs products.

End of the day, I don't think there is anything "wrong" with the AEV suspension, but I'd also state that if you're planning to run 37s and nothing more, there is really no need to go with the AEV suspension. It lifts the truck, but you don't actually need a lift to clear 37s, and it gives you very little additional clearance in brake-over angle.

For what it's worth, the vast majority of guys that off-road their ram HD platform trucks are running Carli or Thuren suspensions. AEV rigs are mostly mall crawlers (outside Chet and a small handful of others).

There is a pretty long thread here, that has some good discussion about the pros/cons of the AEV suspension. It's worth a read prior to you pulling the trigger, either to make you feel more confident in the direction of giving you additional items to consider.

Even though I'm set on sticking to payload numbers as non sensical as it might sound to some people. I would love to hear a knowledgeable contrarian perspective.

You're gonna get a lot of perspectives on payload vs GAWRs. The TLDR from my POV, and a lot of others, is that trucks must stay within a GVWR range in order to be considered a 1/2, 3/4, and 1 ton truck. 10k is the limit for 3/4 trucks (purely from a registration POV). You'll notice that Ford and GM has since enabled additional payload options over the past few years that put a 250/2500 above the 10k limit, but again it's a reg issue.

No issue in going with a 3500, and if you're only hitting fire roads and the like, then a 3500 is going to be more than capable. I would strongly advise considering a lighter weight sway bar (Carli or Thuren have excellent options) as that is going to make the 3500 ride much nicer, especially off road.

Again, it really depends on your end goals. A 3500 will absolutely handle the weight better stock to stock, and if you're willing to upgrade to softer leafs for the 3500 you can get a lot of that softer ride back, same as you can add bags to help account for the weight in the 2500.

If you were going with a heavy hardsided camper I'd say 3500 for sure, but since you're going with a topper camper, a 2500 is also a valid option.

The esteemed @ramblinChet seems to be cruising the backroads fine in his 3500. But it would be nice to have a thread going comparing both experiences, specifically for heavy offroad with the load of campers. But yes, logic tells us the 2500 will be ahead in the rear articulation department.

Articulation on the 2500 will be better than the 3500 off-road for sure, but again it depends on what your needs are. If you had a lot of top heavy weight then I'd say go with the 3500, but less top heavy weight means you can easily enjoy the benefits of the 2500. If you're willing to trade off slightly worse articulation, and a firmer ride then the 3500 is the way to go. If you want something that will ride nicer and offer better off-road articulation, then a 2500 is the way to go, but you will be bumping up or slightly exceeding the legal payload of a well equipped 2500. You will be well within the GAWRs of both though, and I'd recommend you always stay within those ratings.

No matter what, more weight means more wear and tear. A 2500 and 3500 suspension are damn near identical SO to SO, with the singular exception of coil vs leaf.

 

[UglyViking]

Wouldn't the 16% lower 1st gear and 9% lower 2nd gear of the Aisin be the better gear ratio for slow speed driving and overlanding?

The 68RFE does have a slight advantage in 3rd and 5th, but the torque of the HO still has more available at the wheels at those speeds.

Yes, but the details matter. The Aisin has a pretty notable flare shift from first to second gear (at least in the 4th gen SRW I've driven and the DRW I own). That flare shift being right between the two most important gears for off-roading is going to introduce more potential for slipping, shifting, etc. Now, whether or not that is hugely important is a matter of both driver perspective and what you're doing with it.

Another important factor is that the HO weights something like 500lbs more over the SO. The hemi vs the SO cummins weight difference is something like 700-1000 lbs. So you're going another 50% more over the hemi by going with the HO in the best case.

For me, the ability to tune (and fine tune) the trans, plus the better MPG, lower weight and all are more important. I'd also say that I'd much rather have the SO with lockers than the HO without, and with a good gearing choice, I really feel that the SO allows you to have your cake and eat it for "overlanding".

Again, guys will argue these things to death, and at the end of the day I don't think it matters all that much. A gladiator has a vastly better crawl ratio to even the best taco stock to stock, and yet I'd say that there is rarely a time where the taco can't run a trail the gladiator can almost as well.

 

[AH64ID]

Yes, but the details matter. The Aisin has a pretty notable flare shift from first to second gear (at least in the 4th gen SRW I've driven and the DRW I own). That flare shift being right between the two most important gears for off-roading is going to introduce more potential for slipping, shifting, etc. Now, whether or not that is hugely important is a matter of both driver perspective and what you're doing with it.

Another important factor is that the HO weights something like 500lbs more over the SO. The hemi vs the SO cummins weight difference is something like 700-1000 lbs. So you're going another 50% more over the hemi by going with the HO in the best case.

For me, the ability to tune (and fine tune) the trans, plus the better MPG, lower weight and all are more important. I'd also say that I'd much rather have the SO with lockers than the HO without, and with a good gearing choice, I really feel that the SO allows you to have your cake and eat it for "overlanding".

Again, guys will argue these things to death, and at the end of the day I don't think it matters all that much. A gladiator has a vastly better crawl ratio to even the best taco stock to stock, and yet I'd say that there is rarely a time where the taco can't run a trail the gladiator can almost as well.

I have read about the flare shift, but not ever experienced it in my 18, 22, or dads 17. I don't have enough miles on dads 22 to make a comment on that one. Where we hunt the road is slow and rough (another vote for the Thuren active rate sway bar!! the difference is staggering) and I have plenty of 2-1 and 1-2 shifts and don't feel what others describe.

Purely looking at base weights the difference from SO to HO is 160lbs on a SRW truck.

 

[gimmie11s]

Yes, but the details matter. The Aisin has a pretty notable flare shift from first to second gear (at least in the 4th gen SRW I've driven and the DRW I own). That flare shift being right between the two most important gears for off-roading is going to introduce more potential for slipping, shifting, etc. Now, whether or not that is hugely important is a matter of both driver perspective and what you're doing with it.

I hadn't thought about this as it relates to SLOW off roading. Very good point and agree 100%.

 

[hdas]

Purely looking at base weights the difference from SO to HO is 160lbs on a SRW truck.

thanks, the 500 lbs figure did look high.

I would strongly advise considering a lighter weight sway bar (Carli or Thuren have excellent options) as that is going to make the 3500 ride much nicer, especially off road.

These are the type of upgrades I would consider once I have good experience driving the car.

The main issue when facing the SO vs HO is that of lack the information, the anecdotal information is useful in bringing up issues. But in trying to be objective one can arrive to a better answer from 2 angles:

1. Inside View - First Principles: This requires a vast mechanical knowledge and experience, to be able to analyze the components of a system, its interactions from the specifications and be able to make predictions from this.
2. Historical Track Record - The statistics should give us the baseline expectation over a large enough sample.

For me its very hard to approach this problem either way. I'm not in a position to have an inside view, so I have to rely on "opinions" of others. And 2, there's a lack of large high quality, homogenous data. At the beginning of this post I outlined my criteria: Efficiency, Reliability and Performance. It seems that performance can be subdivided in driving experience. And as this threads shows, engine and transmission seem to be two separate entities.

What I gather from this community and other sources, can be summarized by these scores:



Will test the driving experience part. Even if constrained to a short ride on pavement.

 

[AH64ID]

With your planned use I would bet the fuel economy differences are negligible, at best... and certainly not enough to carry double the weight. I personally bet they are so close that I wouldn't even consider the difference. The trucks will weigh about the same and will take the same power to go down the road.

Towing the HO has a potential to drink more fuel, but that really only when it's making more than 850lb/ft.

 

[UglyViking]

Purely looking at base weights the difference from SO to HO is 160lbs on a SRW truck.

I thought the trans alone was close to 200lbs, plus the additional weight of the beefier transfer case and larger axle? I could be very wrong here, the number I had heard was around 500lbs, but it's purely from memory, so I am willing to fully admit I'm wrong.

thanks, the 500 lbs figure did look high.

These are the type of upgrades I would consider once I have good experience driving the car.

The main issue when facing the SO vs HO is that of lack the information, the anecdotal information is useful in bringing up issues. But trying to be objective one can arrive to a better answer from 2 angles:

1. Inside View - First Principles: This requires a vast mechanical knowledge and experience, to be able to analyze the components of a system, its interactions from the specifications and be able to make predictions from this.
2. Historical Track Record - The statistics should give us the baseline answers over a large enough sample.

For me its very hard to approach this problem either way. I'm not in a position of having an inside view, so I have to rely on "opinions" of others. And 2 there's a lack of large high quality, homogenous data. In the beginning of this post I outlined my criteria: Efficiency, Reliability and Performance. It seems that performance can be subdivided in driving experience. And as this threads shows, engine and transmission seem to be two separate entities.

What I gather from this community and other sources, can be summarized by these scores:

View attachment 63286

Will test the driving experience part. Even if constrained to a short ride on pavement.

I would say that most of the criteria you're looking at is going to be somewhat subjective. MPG is a "hard number", but doesn't take into account how people drive. Reliability/longevity of the trans, I'd say the the Aisin clearly has the lead there. The engine, I'd probably weight towards the HO since it's lower compression ratio likely will have it last longer, but at the expense of MPG unloaded.

At the end of the day, both are good choices. You're mostly going to hear folks giving you their personal feedback, and being able to drive both is gonna be your best bet.

With your planned use I would bet the fuel economy differences are negligible, at best... and certainly not enough to carry double the weight. I personally bet they are so close that I wouldn't even consider the difference. The trucks will weigh about the same and will take the same power to go down the road.

Towing the HO has a potential to drink more fuel, but that really only when it's making more than 850lb/ft.

I think it's actually quite the opposite from what I've seen. Unloaded the Aisin tends to be more thirsty, where as loaded they are about the same, with the nod prob going to the Aisin. At least from what I've read.

I can share my personal experience, but I'm looking at a 5th gen SO, 3.73 SRW, with 42k miles I've owned since new vs a 4th gen HO, 4.10 DRW, with 105k miles that I've owned since 100k. Not nearly an apples to apples.

 

[AH64ID]

I thought the trans alone was close to 200lbs, plus the additional weight of the beefier transfer case and larger axle? I could be very wrong here, the number I had heard was around 500lbs, but it's purely from memory, so I am willing to fully admit I'm wrong.

I simply compared the SRW payloads on the SO and HO trucks on the towing chart. Regardless of cab/bed configuration there was a 160lb payload loss on an Aisin when the GVWR was the same.

I think it's actually quite the opposite from what I've seen. Unloaded the Aisin tends to be more thirsty, where as loaded they are about the same, with the nod prob going to the Aisin. At least from what I've read.

I can share my personal experience, but I'm looking at a 5th gen SO, 3.73 SRW, with 42k miles I've owned since new vs a 4th gen HO, 4.10 DRW, with 105k miles that I've owned since 100k. Not nearly an apples to apples.

Very much apples to oranges, but also apples to unicorns since there isn't a 5th gen HD truck yet.

There are simply too many variable in fuel economy, but the power required won't be any different between two trucks that weigh the same so it's really hard to imagine an appreciable difference in economy from tuning and piston differences under normal driving, and the tuning is pretty similar in the cruise range.


Fun discussion!

The OP should buy two identical trucks, one SO and one HO, outfit them the same and then report back on the differences and then keep the best performer.

 

[Brutal_HO]

I don't notice any "shift flare" on my 2020 HO. You most certainly notice the torque management on shifts.

 

[Brutal_HO]

I thought the trans alone was close to 200lbs, plus the additional weight of the beefier transfer case and larger axle? I could be very wrong here, the number I had heard was around 500lbs, but it's purely from memory, so I am willing to fully admit I'm wrong.


I would say that most of the criteria you're looking at is going to be somewhat subjective. MPG is a "hard number", but doesn't take into account how people drive. Reliability/longevity of the trans, I'd say the the Aisin clearly has the lead there. The engine, I'd probably weight towards the HO since it's lower compression ratio likely will have it last longer, but at the expense of MPG unloaded.

At the end of the day, both are good choices. You're mostly going to hear folks giving you their personal feedback, and being able to drive both is gonna be your best bet.


I think it's actually quite the opposite from what I've seen. Unloaded the Aisin tends to be more thirsty, where as loaded they are about the same, with the nod prob going to the Aisin. At least from what I've read.

I can share my personal experience, but I'm looking at a 4.5th gen SO, 3.73 SRW, with 42k miles I've owned since new vs a 4th gen HO, 4.10 DRW, with 105k miles that I've owned since 100k. Not nearly an apples to apples.

FIFY.

 

[hdas]

You most certainly notice the torque management on shifts.

Kindly elaborate on this. Thanks

 

[Brutal_HO]

Kindly elaborate on this. Thanks

Defuels on shifts. I'm sure the 68RFE does it too, maybe just not as noticeable. I can feel the power loss during shifts under hard acceleration.

 

[John Jensen]

What I gather from this community and other sources, can be summarized by these scores:

View attachment 63286

I agree with your conclusions except I would not have given Fuel Efficiency a 33.33% weight setting. I have never bought a truck based on fuel efficiency. Performance has always been my highest priority. Nice job of summarizing and rating all the input.