Towing report 6.4 Hemi...good, bad, underwhelmed

[drittal]

I guess I don't see the glaring fault with the trans others do. The 1-2 shift has quite the gap, but after the first couple times I got used to it. I also don't mind the engine revs or the 2 gear skip. Sometimes it waited too long to shift, but i learned to give it a bit more gas at those points and help it decide to shift. I guess I'm not spoiled coming from either a cummins or 8speed.

 

[RoadDog66]

Ok major update...the Tow/Haul mode sucks! I chose to not use it on the return trip and just put the selector in 5th gear. Wow! Huge difference for the better. It never did the harsh 4-2 downshift (only shifted down to 2nd if I wanted it to) and allowed 3rd gear to be used on the moderate inclines as it should be. It did such a better job towing and eased my concerns about the 6-speed. Mileage went up 1 mpg too.

Still getting used to this diesel sounding gas engine, but much happier now. Now if I could just get the +/- gear selector to work on demand everytime.

 

[SouthernBoy]

I guess I don't see the glaring fault with the trans others do.

I agree with you 100%. Its amazing to me how pampered and finicky people have become. Give 'em more options, they only get more picky and complain more. I come from the day when you had 3 gears in a 727 TorqueFlite or Turbo-400 and the biggest thing we did to 'em was put a $50 B&M shift-kit in the valvebody. We towed gooseneck loads of cattle, horses and sheep all over creation and got by with L1 & L2 on the column. Hell in HS we drove a El Camino with 327 and a Powerglide 2-speed and that thing hauled serious *** and never occurred to use to nitpick the thing. Nowadays they are pumping out more HP and torque figures than ever before from these engines coupled with trannys that have tons of gears, tow/haul buttons and all kinda conveniences and nobody is happy anymore.

Time to go back to 3-on-the-tree or 3-speed on the hump with granny.......

 

[RoadDog66]

I don't think I'm pampered or finicky, just was suprised that this 6-spd is so different from my previous 5-spd. To me an overdrive gear is only for the highway and should be selectable. My +/- selector isn't very intuitive, sometimes I feel the gear change but the dash indicator doesn't show any change.

And the T/H mode on the Ram is just plain weird. I mean completely skipping 3rd and slamming into 2nd and over revving & burning more fuel than needed rather than just using 3rd seems like a miscalculation. It worked perfectly in 5th with no T/H which is why I mentioned it for others to try. Maybe towing over 7K the T/H works fine, but with my 7K trailer and my truck with 3.73's it didn't. Just my observations.

 

[mtofell]

I don't think I'm pampered or finicky, just was suprised that this 6-spd is so different from my previous 5-spd. To me an overdrive gear is only for the highway and should be selectable. My +/- selector isn't very intuitive, sometimes I feel the gear change but the dash indicator doesn't show any change.

And the T/H mode on the Ram is just plain weird. I mean completely skipping 3rd and slamming into 2nd and over revving & burning more fuel than needed rather than just using 3rd seems like a miscalculation. It worked perfectly in 5th with no T/H which is why I mentioned it for others to try. Maybe towing over 7K the T/H works fine, but with my 7K trailer and my truck with 3.73's it didn't. Just my observations.

Yep... my truck seems to hate 3rd gear as well. It almost feels different from the other gears. It's like the transmission isn't linear. Large gap @ 1-2 and 3rd is stuck in no-mans land. It's almost like someone tried to over-thing or over-design it. With the technology out there it just seems they could have done better. I was aware of the mediocrity before I bought the truck and I still bought the truck so I guess I'm not that picky or spoiled

In the whole scheme of things it's a minor annoyance with an otherwise great truck.

 

[River19]

While I have certainly experienced what people complain about......it doesn't really bother me too much or cause me any angst. Do I like the 1-2 chasm of "blah"? Not really but if you get on it from the get-go you don't notice a thing. The one thing that does bug me is the 4-2 slamming downshift when towing horses.....I would like 3rd too, so from now on I'll do it myself......no big deal.

In T/H is where we find the 4-2 fun......I'm thinking it has everything to do with the speed dropping so far down. When I get the 4-2 it is as I drop to 50mph or so on a hill stuck behind some big rig. Normally when I'm closer to 60mph or so I get a nice smooth 4-3 downshift.

 

[SouthTexan]

Yeah I never see 3rd gear either when towing.... or 4th for that matter

I don't think it is being picky or spoiled. I just think it is expecting more which is perfectly fine in something you pay $40k+ for. Each year the bar gets raised and what used to fly 10 or 20 years ago will not today. That is why these trucks get better and better every year(or are suppose to) , and is what encourages competition. There are no doubts that the 6.4L needs a better transmission behind it and I don't blame the 6.4L owners here for expecting more. After all, If no one expected more or for things to get better, then what incentive do these manufacturers have to improve and make things better?

 

[NewBlackDak]

Hoping 86RFE will be ready about the time I am ready for an upgrade.


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[stoney]

Ok major update...the Tow/Haul mode sucks! I chose to not use it on the return trip and just put the selector in 5th gear. Wow! Huge difference for the better. It never did the harsh 4-2 downshift (only shifted down to 2nd if I wanted it to) and allowed 3rd gear to be used on the moderate inclines as it should be. It did such a better job towing and eased my concerns about the 6-speed. Mileage went up 1 mpg too.

Still getting used to this diesel sounding gas engine, but much happier now. Now if I could just get the +/- gear selector to work on demand everytime.

Any issues with not using T/H when towing, assuming you manually shift the tranny into 4th, 5th or 6th?
I have not tried it, but perhaps something to consider the next time I tow my TT.

 

[tjfdesmo]

Time to go back to 3-on-the-tree or 3-speed on the hump with granny.......

I am for that, as long as we go back to a 3/4 ton pickup for $5K.

For me there are two things at play. First, trucks are so obscenely expensive it is no surprise that people's expectations are much higher. The manufacturers' marketing only serves to reinforce those expectations. Secondly, and this is mostly about me, while I understand the numbers that gee-whizz electronics allow these things to generate, I absolutely despise the lack of linear feel, and feeling connected that it gives. I can detect the "man in the box" second guessing my every input. Further, with all of the adaptive stuff, it makes them even less consistent and predictable. At least on the old stuff, if there was a flat spot, or some other annoyance I could pretty quickly find a way to drive around it. I have yet to drive a throttle by wire gasser that felt "normal" to me. The one on my '05 Cummins was as close as I have driven. Several years ago I bought my wife a Volvo wagon, and it had such an unbelievable case of "dead-pedal" that they could not rectify we traded the thing off at a huge loss.

 

[SouthernBoy]

I don't think I'm pampered or finicky, just was suprised that this 6-spd is so different from my previous 5-spd.

Im not speaking to you personally RoadDog66, Im just making an observation about people in general. Doesnt matter what brand or make, the forums are full of the same stuff. We have more options, better & safer stuff than we ever had in the history of vehicles and people whine, moan and complain more than ever. I just come from a different world and background and see things different than most people I guess. Well, I get along real well with Depression era folks I have found, just not many of 'em around anymore.

 

[drittal]

I am for that, as long as we go back to a 3/4 ton pickup for $5K.

For me there are two things at play. First, trucks are so obscenely expensive it is no surprise that people's expectations are much higher.

I'm not sure when 3/4 ton were $5k, but in that much in 1975 equals $22k today. And that is bench seating, 200 hp if you're lucky, leafs and solid axles, am radio, crank windows, manual hubs, carburetor, vinyl flooring, 85mph speedo, 3 sp auto or 4 speed manual, maybe AC, and maybe half the payload and towing.

 

[tjfdesmo]

I'm not sure when 3/4 ton were $5k, but in that much in 1975 equals $22k today. And that is bench seating, 200 hp if you're lucky, leafs and solid axles, am radio, crank windows, manual hubs, carburetor, vinyl flooring, 85mph speedo, 3 sp auto or 4 speed manual, maybe AC, and maybe half the payload and towing.

1976 F-250 Reg Cab, 2WD, Fleetside, 360 2 Barrel, NP435 4 Spd, Vinyl Bench, Rubber Mat, Radio Delete, Manual Steering, Power Brakes, Crank Windows. You're right, they were slow, but I hope to tell you that there is no truck today of any brand that would take the out and out pounding, and unbelievable overloading they took every day in our operation(lumber yard). We even had overhead racks that looked like ladder racks but were super heavy to carry lumber, and they sat in the stake pockets and had plates welded directly to the body. That would crush out the tin foil we deal with now.

Don't get me wrong, I respect some of the capabilities of the new stuff, but like Southern Boy, I remember the old iron and respect what it could do, even if it took a bit of endurance to live with.

 

[spoon059]

I am for that, as long as we go back to a 3/4 ton pickup for $5K.

Exactly... for a $40K+ truck, I would have high expectations as well. My first car was a 17 year old Buick LeSabre that I bought from my sister for $50. Didn't have high expectations for that car. My Ram cost me $40K dollars... I have MUCH higher expectations with that. It isn't being finicky to expect better performance from the transmission of this truck, in my opinion.

The 6.4 seems like a very good engine, but the computer and transmission might be holding it back. I don't put much stock in the Ike Gauntlet tests because I have never driven that road and don't foresee that road in my 10 year plan, but they commented about how frustrated they were with the programming and transmission trying to climb that mountain. Again... great engine, but it sounds like the programming in the transmission is holding it back.

I understand the frustration.

 

[KarL45]

I think you hit the nail on the head when you said transmission gearing. Truth, the transmission is and was, designed for a diesel engine. Something with a torque and power rpm from 18 to 2800 rpm. The 6.4, although about equal in hp, requires at least 4000 rpm to be in the power band. Even with the 4.56 gear, the trans is still too high geared for the engine to achieve max pulling and towing. Am still hoping that Ram will understand that in the next couple of years. If the 6.4 was coupled with the 8 speed trans that is on the 1500, think everyone, including the competition, would be amazed. Am still dreaming. lol

 

[NewBlackDak]

I think you hit the nail on the head when you said transmission gearing. Truth, the transmission is and was, designed for a diesel engine. Something with a torque and power rpm from 18 to 2800 rpm. The 6.4, although about equal in hp, requires at least 4000 rpm to be in the power band. Even with the 4.56 gear, the trans is still too high geared for the engine to achieve max pulling and towing. Am still hoping that Ram will understand that in the next couple of years. If the 6.4 was coupled with the 8 speed trans that is on the 1500, think everyone, including the competition, would be amazed. Am still dreaming. lol

Amazed at how much it breaks. It would need to be the 8HP90 to stand up to the abuse most people put an HD truck through.


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[SouthTexan]

....Truth, the transmission is and was, designed for a diesel engine. Something with a torque and power rpm from 18 to 2800 rpm. The 6.4, although about equal in hp, requires at least 4000 rpm to be in the power band. Even with the 4.56 gear, the trans is still too high geared for the engine to achieve max pulling and towing......

You are right, the gearing in the 66/68RFE is great for a diesels low end torque, but not so much for a gasser with its peak torque at high rpms. Even with 4.56 gears it will not help much as the trans has too tall of gears for a gas engine.

Here is how much the driveline is multiplying the engine's torque to the wheels at peak torque. I also added what speed you have to be at in each gear in order to be at the 6.4L's peak torque at 4,000 rpm given you have the stock 4wd 33.2 inch tires. After 3rd gear, you would have to be traveling too fast to be at the engine's peak torque.

Ram 2500/3500 6.4L 429 lb-ft @ 4,000 rpm with 66RFE transmission with a 4.10 (on 33.2 inch tires)
1st gear--3.23 x 4.10 x 429 = 5,682.25 lb-ft @ 29.9 mph
2nd gear--1.84 x 4.10 x 429 = 3,236.38 lb-ft @ 52.5 mph
3rd gear--1.41 x 4.10 x 429 = 2,480.05 lb-ft @ 68.5 mph
4th gear--1.00 x 4.10 x 429 = 1,758.90 lb-ft @ 96.5 mph
5th gear--0.81 x 4.10 x 429 = 1,424.71 lb-ft @ 119.0 mph
6th gear--0.62 x 4.10 x 429 = 1,090.52 lb-ft @ 155.5 mph

Ram 2500/3500 6.4L 429 lb-ft @ 4,000 rpm with 66RFE transmission with a 4.56 (on 33.2 inch tires)
1st gear--3.23 x 4.56 x 429 = 6,318.66 lb-ft @ 26.9 mph
2nd gear--1.84 x 4.56 x 429 = 3,599.48 lb-ft @ 47.1 mph
3rd gear--1.41 x 4.56 x 429 = 2,758.30 lb-ft @ 61.5 mph
4th gear--1.00 x 4.56 x 429 = 1,956.24 lb-ft @ 86.8 mph
5th gear--0.81 x 4.56 x 429 = 1,584.55 lb-ft @ 107.0 mph
6th gear--0.62 x 4.56 x 429 = 1,212.87 lb-ft @ 140.0 mph



Here are the numbers for the 6.7L CTD. As you can see, a diesel with its low peak torque benefits more with the gearing of the 66/68RFE. The speed you have to be at in each gear to reach the low peak torque of the CTD is much lower allowing you to utilize the engine's peak torque in normal driving or towing conditions in every gear.

Ram 2500/3500 6.7L CTD 800 lb-ft @ 1,600 rpm with 68RFE with 3.42 rear ratio (on 33.2 inch tires)
1st gear--3.23 x 3.42 x 800 lb-ft = 8,837.28 lb-ft @ 14.3 mph
2nd gear--1.84 x 3.42 x 800 lb-ft = 5,034.24 lb-ft @ 25.2 mph
3rd gear--1.41 x 3.42 x 800 lb-ft = 3,857.76 lb-ft @ 32.8 mph
4th gear--1.00 x 3.42 x 800 lb-ft = 2,736.00 lb-ft @ 46.5 mph
5th gear--0.81x 3.42 x 800 lb-ft = 2,243.52 lb-ft @ 57.2 mph
6th gear--0.62 x 3.42 x 800 lb-ft = 1,696.32 lb-ft @ 74.6 mph

 

[6.7CumminsDrvr]

I think you hit the nail on the head when you said transmission gearing. Truth, the transmission is and was, designed for a diesel engine. Something with a torque and power rpm from 18 to 2800 rpm. The 6.4, although about equal in hp, requires at least 4000 rpm to be in the power band. Even with the 4.56 gear, the trans is still too high geared for the engine to achieve max pulling and towing. Am still hoping that Ram will understand that in the next couple of years. If the 6.4 was coupled with the 8 speed trans that is on the 1500, think everyone, including the competition, would be amazed. Am still dreaming. lol

BINGO! Couldn't agree more or said it better myself

I owned an '08 2500 and '10 2500, both were 6.7 CTD's along with the new 68RFE that was designed for it. I remember reading about the "new at the time" trans developed for the new Cummins. It is a better trans than the old 5 speed it replaced but the gearing and spread were developed from day one for the Cummins. 2500 with 6.4 Hemi and 8 speed would be brought home TOMORROW

 

[SouthTexan]

Here is what the 6.4L with an 8-speed that had the same gearing as the one in the 1500 would look like.

Ram 2500/3500 6.4L 429 lb-ft @ 4,000 rpm with 8HP transmission with a 4.10 (on 33.2 inch tires)
1st gear--4.71 x 4.10 x 429 = 8,284.42 lb-ft @ 20.5 mph
2nd gear--3.14 x 4.10 x 429 = 5,522.95 lb-ft @ 30.7 mph
3rd gear--2.11 x 4.10 x 429 = 3,711.28 lb-ft @ 45.7 mph
4th gear--1.67 x 4.10 x 429 = 2,937.36 lb-ft @ 57.8 mph
5th gear--1.29x 4.10 x 429 = 2,268.98 lb-ft @ 74.8 mph
6th gear--1.00 x 4.10 x 429 = 1,758.90 lb-ft @ 96.5 mph
7th gear--.84 x 4.10 x 429 = 1,477.48 lb-ft @ 114.8 mph
8th gear--.67 x 4.10 x 429 = 1,178.46 lb-ft @ 143.9 mph

 

[Ratket]

wow-- props on the charts.. thanks those are awesome