Cummins SO & HO

Disclaimer: Links on this page pointing to Amazon, eBay and other sites may include affiliate code. If you click them and make a purchase, we may earn a small commission.

68PowerWagon

Senior Member
Joined
Nov 26, 2015
Posts
1,666
Reaction score
976
Location
Dayton, Ohio
Ram Year
2022 Laramie 3500
Engine
6.7 CTD
I may be purchasing one of these in a year or two & wanted some feedback from people who have owned both. Is there a considerable amount of difference in performance? And is there a considerable amount of difference in fuel mileage? I have heard the Aisin, that comes with the HO, needs to be serviced more often. If they are running the sale on HO's like they are now when I purchase, it's almost a no brainer to go that route.
 

Fuel35 67

Senior Member
Military
Joined
Aug 18, 2019
Posts
311
Reaction score
194
Location
Hanford
Ram Year
2011
Engine
6.7 Cummins
No trans tuning not yet for the Aisin. Torque management doesn’t allow either engine to put down the torque that the engine has. It’s less likely to give ya any trouble over the 68rfe.
 

chri5k

Senior Member
Supporting Member
Joined
May 24, 2019
Posts
1,925
Reaction score
2,902
Location
USA
Ram Year
2016
Engine
Diesel
Depends on what you are hauling and the price difference. If you are near the limits of the truck fairly regularly, the HO might make sense. If it will be a grocery getter with an occasional 10,000 lb trailer haul then the SO might make sense. Heck if its the latter a 2500 also makes sense.
 

tjfdesmo

Senior Member
Joined
Apr 15, 2014
Posts
2,255
Reaction score
4,038
Location
AZ
Given your time frame the new transmission should be out, and I hope it's a winner. The Aisin is plenty stout, but it's sort of a stumblebum in operation. As mentioned, Ram's torque managenment is very heavy-handed. I hope the next trans allows them to tame that down, as it really handicaps the Cummins.
 
OP
OP
68PowerWagon

68PowerWagon

Senior Member
Joined
Nov 26, 2015
Posts
1,666
Reaction score
976
Location
Dayton, Ohio
Ram Year
2022 Laramie 3500
Engine
6.7 CTD
Depends on what you are hauling and the price difference. If you are near the limits of the truck fairly regularly, the HO might make sense. If it will be a grocery getter with an occasional 10,000 lb trailer haul then the SO might make sense. Heck if its the latter a 2500 also makes sense.
Pulling 13.5k 5th wheel now with my 2500 gas which is at it's max. Want something that can handle that & more if we upgrade trailer in a few years. I would like to wait to see if they come out with a heavy duty Asin/ or Torquflite 8 speed for these, so hopefully they will be out in the next year or two. I am not opposed to the HO unless it just gets 2-4mpg less fuel mileage. For what they are running now it would be well worth the extra money for the more torque & better transmission.
 

stevenP

Senior Member
Joined
Nov 9, 2014
Posts
641
Reaction score
621
Location
northern Indiana
Ram Year
2022 2500 Longhorn
Engine
6.7L Cummins
I have both the 2500 CTD powered.. with the 68rfe auto trans, and a 3500 dually with the aisin and CTD HO. Driving them normally I cant tell alot of difference between the two. DSCF0282.JPG I havent hauled anything big with the 2500, I kinda use it as a car. My dually, I use like others here to pretty much haul my 15k fifth wheel around only. I do think the aisin clunks harder as it shifts, if your lead footing it.
 

RABRAZ

Junior Member
Joined
Mar 12, 2021
Posts
3
Reaction score
0
Location
TEXAS
Ram Year
2021
Engine
6.7
I too wound up with a similar question. I was driving a 2012 F350 6.7 SRW and was completely satisfied with the truck. Towed my 13k toyhauler fiver like a dream and I only had a few problems with the truck that I had cleared up. Then the DW showed me a pic of a new fiver. Cedar Creek 385TH. More living than toy oriented. Also about 6k heavier dry tripple axle. The dealer would not sell me the trailer with the Ford. He said the ratings just did not work out, liability, yada, yada. So after much shopping I decided on the 2021 3500 Longhorn Limited DRW 6.7 HO. My first Ram. So far my only complaint is the fuel mileage. First trip of 300 miles with the Longhorn I averaged 8.9 mpg towing the new trailer dry. I hope it gets better as it breaks in. I will say the extra rubber on the ground does make a difference. My opinion would be to stick with a gasser unless you intend to do a lot of heavy towing. Just an opinion.
Regards and stay safe on the road.
 

jejb

Military
Joined
Apr 7, 2020
Posts
1,569
Reaction score
1,439
Location
NW Arkansas
Ram Year
2022
Engine
6.7 Cummins
My opinion would be to stick with a gasser unless you intend to do a lot of heavy towing. Just an opinion.
I generally agree with that, but would add there are other circumstances that help to justify the diesel, even if you're not towing a triple axle fiver. Like if you live in hilly or mountainous terrain, or tow at altitude a lot (turbo equipped motors do much better up in the clouds).
 
Last edited:

Scottly

Senior Member
Joined
Oct 11, 2018
Posts
1,185
Reaction score
2,197
Location
Safety Harbor, FL
Ram Year
2021
Engine
HO 6.7 Cummins
Had a 2018 ram 2500 with SO Cummins/68RFE, now have a 2021 Ram 3500 SRW with HO Cummins/Aisin combo. No real difference in power to the ground during normal driving. What is different is: A) Aisin has a lower 1st gear, which it quickly shifts out of....But off the line, pulls better and gives the turbo time to spool up. 2) The Aisin shifts "goofy" compared to the 68RFE. When in 2nd gear, it acts like it doesn't know where to go or what to do sometimes. It barks the tires going into third gear. The rest are OK. All the goofiness goes away if you shift to tow/haul mode. Then it shifts like an old Chevy T400 with a shift kit in it...Bangs every gear, and holds it for awhile if you back off the throttle. The 68RFE would upshift like crazy when you backed off the throttle, then struggle to find the correct gear when you got back in the throttle. The Aisin shifts more comparable to the Allison 10sp in my Chevy(except for the goofy 2nd gear action). 3) HO Cummins drinks more fuel around town, but no more than my Duramax did. 4) the HO Cummins is the new version of the 6.7, and it's a bit quieter than the 2018 was. 5) Not for nothing, but the 2021 is a lot easier to change out the headlight bulbs than the 2018 was. :)
 

HDGoose

Senior Member
Military
Joined
Mar 17, 2016
Posts
516
Reaction score
478
Ram Year
2020
Engine
L6 Diesel HO
I can only compare my 2013 RAM 2500 SO diesel CC SB dually to my 2020 RAM 3500 DRW HO diesel Aisin CC LB. Unloaded Icannot tell the difference. Pulling 12k-18k trailers, the HO pulls harder, quicker, and quieter. I never lacked anything in the WV/TN/NC mountains with a 12k toyhauler. I bought the 3500 DRW in preparation to buy a newer, larger camper in a couple of years.
 

thebuilderman

Senior Member
Joined
Aug 29, 2020
Posts
111
Reaction score
77
Location
Colorado
Ram Year
2006
Engine
5.9 Cummins
Pulling 13.5k 5th wheel now with my 2500 gas which is at it's max. Want something that can handle that & more if we upgrade trailer in a few years. I would like to wait to see if they come out with a heavy duty Asin/ or Torquflite 8 speed for these, so hopefully they will be out in the next year or two. I am not opposed to the HO unless it just gets 2-4mpg less fuel mileage. For what they are running now it would be well worth the extra money for the more torque & better transmission.
From everything I read, which has been a lot, they should have the new tranny available very soon. I heard mid 21 or end of 21. Either the new ZF or an Allison. Either will be ok with me although I think I’d prefer the 9 speed Allison. That means they will choose the ZF 8 speed.
 
OP
OP
68PowerWagon

68PowerWagon

Senior Member
Joined
Nov 26, 2015
Posts
1,666
Reaction score
976
Location
Dayton, Ohio
Ram Year
2022 Laramie 3500
Engine
6.7 CTD
I think anything more than 6 forward gears is a waste.
Yeah growing up when 3 speed was the norm I get what you are saying, but after you drive something with an 8 speed it's like WOW. The 8 speed in our Durango is so smooth & gives the little 3.6L great performance. I can only imagine what these larger engines with a 8-10 speed is like.
 

Fuel35 67

Senior Member
Military
Joined
Aug 18, 2019
Posts
311
Reaction score
194
Location
Hanford
Ram Year
2011
Engine
6.7 Cummins
It’s like the 545rfe, sometimes it would skip second prime depending on throttle position. The 68rfe has the correct gear ratios, and in my opinion, the proper amount of gears. Too bad FCA decided to make 5/6th gear so small.
 
Top