6.4 with 8 speed?

[Bearcatrp]

Am at a cross roads trying to decide if I want a diesel or 6.4 with gas. The added maintenance with the cummins and dealing with DEF has me having second thought. Looked at a diesel yesterday, then talked to the maintenance department on service costs. $400 a pop just to service the fuel filters at 15,000 miles so basically every oil change at 15,000 miles. Wow. Thinking 1 ton 6.4 with 8 speed. Has a 50 gal gas tank. I pull a 10,000 lb 5th wheel with my 2017 Ram 2500 CC with 6.4 and 6 speed. Climbing hills going from minnesota to colorado sucked. 4th gear allot of time and some 3rd gear and high RPM's. Will the 8 speed do better? Reading allot of posts on diesel mileage pulling and seems about the same a gas except they can climb hills allot better. If you have a 6.4 and 8 speed pulling 10,000 in hills, please chime in. Can save $10,000 by going gas. Plus can get $3000 more than I paid for my current truck. Thanks.

 

[Firebird]

I had a 2018 with 6.4 and 6 speed, my new 8 speed with 6.4 blows my old truck out of the water!

 

[Bearcatrp]

How much lbs are you pulling? Big hills?

 

[HEMIMANN]

I had a 2018 with 6.4 and 6 speed, my new 8 speed with 6.4 blows my old truck out of the water!

Stop that!! lol

2017 Ram 2500 CC Laramie 4x4
6.4 Hemi
6 speed
3.73 gears

 

[Riccochet]

I was in the same boat. Considered a diesel, but couldn't justify the maintenance costs or inevitable repair costs. Went with a 2020 2500 6.4 w/ 8 speed. It pulls my 8300# travel trailer with ease on grades. Granted, it's not as easy as a diesel, but it gets the job done.

The thing about gas motors is they make their power and torque in upper RPM's. So, running 4500+ RPM's on grades is where it should be. If it wasn't it would be lugging, and that's bad on gas motors.

The 8 speed is great, loaded or unloaded. It does hunt gears from time to time, but that's to be expected on a high geared close ratio transmission.

I will say that around 11,000 lbs is about all I'd want to pull with a gasser. Beyond that is diesel territory.

 

[Bearcatrp]

Going between cheyenne and laramie in route to colorado pulling my 5th wheel had me going between 3rd and 4th with high rpm's. Would think the 8 speed would reduce that looking at the gear ratio's between the two. Going down that pass, the hill descent kicked in to high rpm's. My truck handles my 5th wheel fairly fine on flat lands and small hills. Bucking winds, I don't get out of 5th gear. Used to own a 2014 ram 1500 with a 8 speed. The top 2 gears were over drives. Are these new ones the same?

 

[crash68]

The top 2 gears were over drives. Are these new ones the same?

The 8HP75 8spd in the HD trucks is the same with 7 & 8 being "overdrive" gears. It not like the trans of old that you didn't want to use OD gears while towing, just use the Tow/Haul mode and it will use the gears it needs to.

 

[Travelin Ram]

The 8 speed will pull a little stronger because it’s got more gears to help keep the engine near peak torque or HP. But there’s no magic sauce to keep it from revving, the gas engine needs to rev to pull a grade.

I would not own a gas truck for a big trailer. That’s not a financial decision, it’s a preference. Anyone who’s driven both knows why.

Just my .02 but if your towing is recreational why count pennies? When I’m on the road it’s not like work, where profit margins were factored in. I’m out here to enjoy myself. Big fivers are a luxury unless you’re traveling for work and living in them.

 

[retired]

I just did a 3000+ road trip (montana to Minnesota) so similar to Minn to Colorado and I did not pull a trailer just have a light weight GFC camper and not all that impressed with the 6.4L, 4.10's and 8speed, it is pretty gutless. If I were pulling 10K I would get the diesel and I have never even had a diesel . Ram needs to up their game in the big gasser department. I don't mind the revs going up passes I know these are built to handle rpms but lack of engine braking coming down hills seems like it would be killer if I had a 9000 lbs trailer pushing me.

 

[NH RAM]

I'm pulling a Cougar 30RLS which is 11k gross, probably 10,000 - 10,500 loaded. I haven't crossed a scale yet as there have been none along my path. I have pulled in the hills of New England and it does really well. I haven't hit any real mountains to talk about pulling at elevation, but there are some pretty good grades between New Hampshire, Vermont, and Maine to test the combination and I'm very pleased. Most of my travels involve sub 6% grades and elevations below 4,000 feet.
My trip to Quechee, VT has a lot of 5-6% grades but according to flattestroute.com there is a small section that is 12% after crossing the Connecticut River. I can maintain highway speed - during the trip it isn't afraid to hit 3k and occasionally 4k rpm. Would a diesel be better- sure- but a couple things kept me in a 6.4:
1. $9500ish added cost for a Cummins, not H.O.
2. DEF issues (maybe not common, but enough to pause and think) including freezing tanks during winter
3. 2,000# payload isn't uncommon on a Cummins 2500 and diesel 3500's are unicorns around here- 2000# isn't enough payload for a 5w and gear
4. CP4 longevity seems to be hit or miss
5. Diesel fuel is more expensive
6. More expensive oil changes and added fuel filter changes
7. 1600# vs 1100# available before front axle is max'd out per GAWR means an XV2 plow puts a Cummins 2500 nearly at max capacity
8. The 8HP75 is a great transmission with good gear spacing; this made the choice to get a 6.4 far easier than the pre-2019 trucks with the 66rfe

With all that said, if money were no object, I would opt for the Cummins 3500. I pull my campers all over- I have a trip coming in August from New Hampshire to North Carolina and Back. Last year I went from New Hampshire to South Dakota and back, but that was with a 7500# travel trailer. I'm interested to see how it does pulling the 5w to North Dakota. If my trips were local, I wouldn't consider a Cummins. If a deal comes along I may find myself in a Cummins 3500 but I don't anticipate that happening anytime in the foreseeable future.

 

[HEMIMANN]

Yep - $9,000 isn't pennies for me. I'd have to give up something else for that luxury below 10,000 lbs load I have. Life is all about tradeoffs. None of us has infinite money.

 

[Bearcatrp]

Thanks for all the replies. If I had the deep pockets, wouldn’t hesitate on diesel. But after looking into maintenance cost for these newer diesels, I’ll pass. After looking around my state, both 3/4 and 1 tons are running close to same price, which is nuts. Can save $10 grand going gas or even a little more. Would be nice if Ram had a 10 speed for the gas HD’s. Think it would be optimum.

 

[Farmer Fran]

You get a lot more payload with the gasser

 

[Firebird]

Stop that!! lol

2017 Ram 2500 CC Laramie 4x4
6.4 Hemi
6 speed
3.73 gears

Hahahahaha!!!
There is truly no comparison.

 

[Firebird]

How much lbs are you pulling? Big hills?

I pull 9000 pounds, but the biggest Hills I pull are N Georgia. I live in Florida, so don't have to deal with crazy hills

 

[Riccochet]

You get a lot more payload with the gasser

That's the kicker right there for 2500's. A well equipped 2500 diesel isn't much better than a 1/2 ton when it comes to payload. In my opinion there's no logical sense in buying a 3/4 ton diesel.

 

[Firebird]

That's the kicker right there for 2500's. A well equipped 2500 diesel isn't much better than a 1/2 ton when it comes to payload. In my opinion there's no logical sense in buying a 3/4 ton diesel.

True, my contractor used to have a 2020 Cummins 2500 Mega Cab Laramie with everything on the options list. Payload was right at 1200 pounds. CP4 let go, so he got the same truck again, except 2021 HO Limited Mega Cab 3500 with everything. Payload is now 3600 pounds. His Payload is only 500 pounds more than my lowly 6.4 2500. However, he has MONSTER power!

 

[Riccochet]

True, my contractor used to have a 2020 Cummins 2500 Mega Cab Laramie with everything on the options list. Payload was right at 1200 pounds. CP4 let go, so he got the same truck again, except 2021 HO Limited Mega Cab 3500 with everything. Payload is now 3600 pounds. His Payload is only 500 pounds more than my lowly 6.4 2500. However, he has MONSTER power!

That's why I went with a 2020 2500 6.4. I have 3090# of payload. More than enough for my travel trailer, or a mediumish sized 5th wheel if I upgrade.

 

[Bearcatrp]

Anyone know what RPM max torque is? My six speed is 4th gear. Looking at gear ratio, it’s hard to tell. Also, in tow haul mode, are the top two gears excluded while driving? Am hoping the 8 speed in the 2021’s are not like what is in the 2014’s with the 3:23’s, top two over drive.

 

[HEMIMANN]

Not aware of any published curves by FCA, but I'd trust Diablosport's benchmarking....

DiabloSport Tuning Now Supporting 2017-2018 Ram 2500-3500 6.4L

The 2017-2018 6.4L equipped Ram trucks are a popular choice for those that want the power of a diesel but prefer a gasoline motor. We know that truck owners want the most out of their trucks whether it be for towing, daily driving, or for serious passing power. The DiabloSport tuning solutions...

www.diablosport.com

This truck will have the 66RFE transmission, but they don't say what axle ratio is. Most were ordered with 3.73, like mine.