Yet Another 6.4 3.73 or 4.10 Question

[Trailmaker]

2018 3500 CC big horn 6.4 & 4.10's. in mine. Tow little 6x10 enclosed trailer loaded with tools, ladders, conduit & misc. A lot of interstate driving 70mph its 7-10 avg mpg in tow/haul. With my 20ft gooseneck and 8k mini-x I'm regretting not having the Cummins. Even with the 4.10's a small elevation change and it starts looking for RPM's. The 6 speed just doesn't seem to be a good match. Anything under 2000 rpm it just struggles. And in tow/haul no matter how I accelerate it holds 1st gear to 4000+ then leaps to 2nd, only to then grab 3rd before 2nd has a chance to do anything. By then 3rd bogs down causing it to downshift. When they did recall for power train control update I asked the dealer if holding 1st like that was normal. They said if its shifting then its operating normally. Ok,thanks for looking into my concerns. I plan on keeping it another year till warranty gets close to done and I will be looking at all of the big three where before I went only to Ram. No experience with the 8sp so maybe they are matched better to the 6.4 and the 2500/3500 trucks.

Yes better matched with the 8 speed. I haul more then tow but I have a 16’ that I use for projects and my tractor and I don’t experience the things you are speaking of.

 

[Jeff Courtney]

Glad to hear that. My first MOPAR was also my 1st new truck purchase in '98. I've owned a '05, '07, which were all 1500's. I've had a 2010 2500 6.7 cummins, '11 2500 5.7, and this '18 with 6.4. They all were great to me. The one I miss is the Cummins. Everything about that truck just seemed better than my '18. My next purchase will include a trailer tow in the test drive.

 

[Trailmaker]

No doubt the 6.7 is the ultimate for towing. Unfortunately it comes with a 10k price tag. Thankfully the 8 speed really helps with pulling a load, to overcome the torque difference between the 6.4 and the 6.7l

 

[dhay13]

I tow my 9000lb boat with mine with 4.10's. Have never really towed it far or up big hills but when I have towed it it was fine. My son has the exact same truck and towed his 8500lb camper 1500 miles to North Dakota. He complained at first but mainly because he wanted the diesel but didn't have the time to find one reasonable. His company only gave him 1 week notice about going to ND and he wasn't allowed to tow with a company truck. He looked at a few diesels but on new ones they weren't willing to budge off their price and the 2 used ones he found were only a few thousand under a new one and they had 40,000 miles on them. So the 6.4 did fine and he admitted once he got there that it towed fine. He got about 8-8.5 MPG

 

[ScrubsR1]

2018 3500 CC big horn 6.4 & 4.10's. in mine. Tow little 6x10 enclosed trailer loaded with tools, ladders, conduit & misc. A lot of interstate driving 70mph its 7-10 avg mpg in tow/haul. With my 20ft gooseneck and 8k mini-x I'm regretting not having the Cummins. Even with the 4.10's a small elevation change and it starts looking for RPM's. The 6 speed just doesn't seem to be a good match. Anything under 2000 rpm it just struggles. And in tow/haul no matter how I accelerate it holds 1st gear to 4000+ then leaps to 2nd, only to then grab 3rd before 2nd has a chance to do anything. By then 3rd bogs down causing it to downshift. When they did recall for power train control update I asked the dealer if holding 1st like that was normal. They said if its shifting then its operating normally. Ok,thanks for looking into my concerns. I plan on keeping it another year till warranty gets close to done and I will be looking at all of the big three where before I went only to Ram. No experience with the 8sp so maybe they are matched better to the 6.4 and the 2500/3500 trucks.

Jeff, your experience with the 6.4 and 4.10s is very similar to mine. When I purchased my '17 Bighorn back in April, I hooked it up to my 8k trailer and found it adequate. But what really swayed me was the price...much lower than a similarly equipped Ford or Chevy.

The frustration began to set in when I did more jobs up in the nearby hills and mountains. Any type of grade seemed to shut my truck down completely. My previous truck was a cummins so this was uncharted territory. What really soured me on the truck took place on a family campout near Stanley Idaho. I was pulling a small utility trailer loaded with a polaris razor(combined 3500lbs) and a couple motorbikes in the bed of the truck. We were midway up a five mile steep grade with a stiff headwind . I had my truck pegged and was managing just over 50mph. Out of nowhere my brother comes blowing by us in his f150(3.5 ecoboost) pulling a 9k camper. I was stupified and fuming at the same time. My wife oblivious to my rage, lightly tapped on my shoulder and asked "isn't your brothers truck just a little half ton?" I just nodded and we left it at that.

Anyways, I've only owned this truck for seven months and I've already worked up a trade in agreement with the local dealership on a new cummins. Employee pricing and year end rebates make it so tempting...

Btw, living at an elevation of almost 5000' obviously contributes to hp loss. It would be interesting to know by what factor?

 

[tjfdesmo]

Roughly 3.5%/1K Ft

 

[AFMoulton]

Put a turbo or a supercharger on the 6.4, you won’t have the loss at altitude. That’s why the EcoBoost can do that, that’s what helps the Cummins maintain performance everywhere, forced induction is a great equalizer.


2018 Ram 2500 6.4L 4x4
Amsoil SS 0W-40

 

[dhay13]

Has to be the altitude or something. My truck pulls my 9000lb boat with ease. Haven't went up any huge hills and have the 4.10's but have never even had a slight hint of trouble. Barely knows it's back there

 

[U&A]

4:10’s at a minimum. But i say...

33”-35” tire need 4.56’s - 4.88’s

35” or large tire needs 5.13’s

I have 35’s and 4.88’s. They work great. But id love to have 5.13’s.


Sent while firmly grasping my redline lubed RAM [emoji231]

 

[AFMoulton]

4:10’s at a minimum. But i say...

33”-35” tire need 4.56’s - 4.88’s

35” or large tire needs 5.13’s

I have 35’s and 4.88’s. They work great. But id love to have 5.13’s.


Sent while firmly grasping my redline lubed RAM [emoji231]

After gearing, put a supercharger on it. You won’t have any power loss at any altitude then!


2018 Ram 2500 6.4L 4x4
Amsoil SS 0W-40

 

[U&A]

After gearing, put a supercharger on it. You won’t have any power loss at any altitude then!


2018 Ram 2500 6.4L 4x4
Amsoil SS 0W-40

Can i give you the phone so you can convince my wife i need a super charger...? [emoji1787]


Sent while firmly grasping my redline lubed RAM [emoji231]

 

[dhay13]

Can't say for sure about the OD gears between the Wrangler and the Ram but daughter has a 2016 Wrangler with 35's and had 4.88's put in and now she can't drive it to work. I told her 4.56 was the absolute steepest I would go and that was even pushing it. Now on the highway her engine is cranking. She bought a Superchips to re-calibrate her speedometer but it is over 3000 RPM at over about 55 or so. I think she said it's over 4000 RPM on the highway. I have only driven it a few times since she did all this so my numbers are by memory based on what she told me but it is basically undriveable unless under 40 MPH. She is talking about going to 37's to help a little.I told her 4.56's at the most but the shop she bought everything at talked her into 4.88's and she regrets not listening to me now.

I know I would never want 4.88's in my truck with my stock tires and I never plan to go with taller tires. 4.56's MIGHT be ok but I don't need them for what I tow. If you plan to swap gears use a gear calculator and factor in what type of driving you will be doing. My daughter used to work 3 miles from her house so even with 4.88's her Jeep was fine but she changed jobs and not drives on the highway about 70 miles a day. She ended up buying a car and the Jeep sits in the garage collecting dust now.

A little more than dust here but this is it. Looks great.




And what I tow

 

[U&A]

Can't say for sure about the OD gears between the Wrangler and the Ram but daughter has a 2016 Wrangler with 35's and had 4.88's put in and now she can't drive it to work. I told her 4.56 was the absolute steepest I would go and that was even pushing it. Now on the highway her engine is cranking. She bought a Superchips to re-calibrate her speedometer but it is over 3000 RPM at over about 55 or so. I think she said it's over 4000 RPM on the highway. I have only driven it a few times since she did all this so my numbers are by memory based on what she told me but it is basically undriveable unless under 40 MPH. She is talking about going to 37's to help a little.I told her 4.56's at the most but the shop she bought everything at talked her into 4.88's and she regrets not listening to me now.

I know I would never want 4.88's in my truck with my stock tires and I never plan to go with taller tires. 4.56's MIGHT be ok but I don't need them for what I tow. If you plan to swap gears use a gear calculator and factor in what type of driving you will be doing. My daughter used to work 3 miles from her house so even with 4.88's her Jeep was fine but she changed jobs and not drives on the highway about 70 miles a day. She ended up buying a car and the Jeep sits in the garage collecting dust now.

A little more than dust here but this is it. Looks great.




And what I tow

The 66rfe have some stupid gear set sizes.

My 35’s and 4.88’s i can go 70 mph and be at about 2100 rpm. With 33’s you will be right around 2200rpm

At 80 MPH i am just about 2400rpm. With 33’s you will be at 2500.

Not to be rude here as I’m not trying to be but do your research before making assumptions.

Put in 68RFE because the 66RFE has the same gear set.

Use this link

Add about 50-75 rpm for wind resistance.


http://www.grimmjeeper.com/gears.html

You don’t need to fill out every column. Just select your transmission in the drop-down menu. Then just put in your gear ratio and tire size.





Sent while firmly grasping my redline lubed RAM [emoji231]

 

[Mountaineer83]

I have 4.10s stock and I'm torn right now between the 4.88 and 5.13. I tow heavy, but even daily it would be like driving in 5th gear, which happens a lot anyway due to the hills in WV.

 

[dhay13]

Not to be rude here as I’m not trying to be but do your research before making assumptions.

Which is why I said in my very first sentence that I wasn't sure about the OD gear differences between the Wrangler and Ram so it wasn't an 'assumption' but more of 'do your research before spending money'

 

[68PowerWagon]

Can't say for sure about the OD gears between the Wrangler and the Ram but daughter has a 2016 Wrangler with 35's and had 4.88's put in and now she can't drive it to work. I told her 4.56 was the absolute steepest I would go and that was even pushing it. Now on the highway her engine is cranking. She bought a Superchips to re-calibrate her speedometer but it is over 3000 RPM at over about 55 or so. I think she said it's over 4000 RPM on the highway. I have only driven it a few times since she did all this so my numbers are by memory based on what she told me but it is basically undriveable unless under 40 MPH. She is talking about going to 37's to help a little.I told her 4.56's at the most but the shop she bought everything at talked her into 4.88's and she regrets not listening to me now.

I know I would never want 4.88's in my truck with my stock tires and I never plan to go with taller tires. 4.56's MIGHT be ok but I don't need them for what I tow. If you plan to swap gears use a gear calculator and factor in what type of driving you will be doing. My daughter used to work 3 miles from her house so even with 4.88's her Jeep was fine but she changed jobs and not drives on the highway about 70 miles a day. She ended up buying a car and the Jeep sits in the garage collecting dust now.

A little more than dust here but this is it. Looks great.




And what I tow

Yeah I think the shop should have been a little more responsible & looked at the tranny gearing before they pushed her to the 4.88's. Plus it is probably the 3.6 so that is going to rev a littler more than a V8. It would be nice if they would re-gear it for her & eat the labor.

 

[Jeff Courtney]

Getting passed by a F150, ouch! The comment about forced induction of whichever type suites each person is right. Swapping to lower gears is another route and a must if larger wheels/tires are used. Its all about budget for me. If I was gonna spend that much to bring the gas 6.4 ip to par I'd just trade to the cummins. I like gas trucks but function and reliability are main needs for me.

 

[FlatbedHemi]

Thanks for the scoop. Sticking with 2017-2018 for now, but may end up with an end of year 2019 as I will be shopping in January.

Dont know if you've made your decision yet, but If I were in the market, I would get the 8 speed with the 4.10s. From what I have found, the new 8 speed is gonna gear you a tad lower than my 15 with 4.88s, but with a couple actual overdrives for cruising. Thats if I found the right gear ratios for the 8 speed.

Anyone want to check me on that, in case Im wrong.