Have they ran the 6.4 with the 8 spd up the Ike

[RBinNC]

I average 12mpg empty in my 2019 6.4/8 speed long bed. Crew cab 4x4 4.10 rear. And I don't drive it hard. So yeah. At that point mpg is just gonna suck no matter what.

 

[CMV157]

I contacted TFL and like was previously said, the 8 speed truck is waiting in Michigan but they are not allowed to pick it up yet. I sure hope they get it soon. I'm really curious, I bet it goes up far better than the 6 speed. I've got the 6 speed truck now and although I love the truck, I really wish it had the 8 speed. I don't mind the 1st gear ratio. The issue with the 6 speed is the 1-2 spacing. 2nd is way way too tall and I have 4:10.

 

[RandomRam]

I suspect the Ram 6.4/8HP combo will out perform the GM trucks and the 6.2 Ford, but Godzilla will be king at the cost of a lot more gasoline burned. GM’s 6.6 is crippled by their 6 speed.

 

[mylittlejoey]

I agree with CMV157, I've also got the 6 speed truck (2016) now and although I love the truck,6.4/4.10. Tow mode is brutal on hills with 7200lb TT, so I don't use it anymore. Wish I had an 8 speed.

 

[tjfdesmo]

I contacted TFL and like was previously said, the 8 speed truck is waiting in Michigan but they are not allowed to pick it up yet. I sure hope they get it soon. I'm really curious, I bet it goes up far better than the 6 speed. I've got the 6 speed truck now and although I love the truck, I really wish it had the 8 speed. I don't mind the 1st gear ratio. The issue with the 6 speed is the 1-2 spacing. 2nd is way way too tall and I have 4:10.

Totally agree on the 1-2 hole. As to 1st gear, hitch up to 17K lbs, and see how much throttle, and torque converter slip it takes to get it started on a grade. Not as bad as backing a heavy load uphill with my old 48RE, but definitely less than ideal. My '15 also had 4.10s.

 

[ronheater70]

Well thats the whole point with the 8 speed is to fix a problem area with the HD truck, that being the 6 speed. It performed well enough with it (except on the Ike) but it was ahorrible combo to that engine. My Biggest complaint was the transmission and I really didnt enjoy it with 10K pounds, I dont know how you some guys are towing 12K or more with it. Mine had the 3:73 though, maybe 4:10s are that much better but I doubt it.
I would have been happy with the 6 speed if it just had lower ratios. I wouldnt mind turning afew hundred more rpms at highway speed to get the truck moving a little easier and to avoid that horrible 1-2 gap. Really the 8 speed from everything I read has really mad the truck competetive now. Im anxioous to see it's Ike run.
As for the Ford 7.3, That trucks a monster. It's using gas, but your getting the end result it is intended for, great towing abilities.

 

[Sandevino]

A neighbor has a 2017 2500 nearly identical to mine (6.4L, 4x4, CC, 3.73’s and Tradesman) and he tows a 10,000# trailer for his mobile millwork business. We struck up a conversation and I ended up taking a ride with him while he towed his trailer. We switched trucks and he towed with mine. The look on his face said it all.

The 2017 swapped between 4th and 5th depending on speed and grade never making it to 6th gear. It kicked down to 3rd going up a decent hill at 65mph on US-75 through North Texas. My 2020 stayed in 6th and 7th and didn’t kick down to 4th or 5th where his kicked down to 3rd gear.

Granted, we weren’t too scientific here, but tried to keep everything as consistent as possible. He drove both runs, same trailer, both full of fuel, time of day within an hour with the same weather.

 

[tjfdesmo]

US-75 is so rough, it's hard to keep the trailer on the ground

 

[sandawilliams]

I have no doubt the 8 speed is better than my 6. The issues to me is the ones that don't tow much and don't anticipate the terrain. I tow 8800# with another 1500 in the bed. I tow a lot in the mountains of Colorado. I see the terrain changes ahead and manually downshift prior to getting there. Keep the RPM's up and avoid the truck from losing momentum. As far as taking off on a slope. Having hauled heavy equipment (tractor/trailer) in Colorado truckers know not to stop on the uphill side of the mountain when loaded. You can have 1000 ft lbs of torque and your going to have a hell of a time taking off.

 

[Sandevino]

Having hauled all kinds of heavy things coast to coast I’m appalled by the overwhelming lack of skill and over abundance of confidence most drivers have. I over prepare and expect people to act stupid as they usually don’t disappoint.

 

[wyo2track]

The 2017 swapped between 4th and 5th depending on speed and grade never making it to 6th gear. It kicked down to 3rd going up a decent hill at 65mph on US-75 through North Texas. My 2020 stayed in 6th and 7th and didn’t kick down to 4th or 5th where his kicked down to 3rd gear.

Good information. Thank you. I am chewing on this information a little. It does scratch that curiosity itch I had on how the 8 spd would be at hwy speed. I have no doubt that getting up to speed with the 6.4/8 is much better than with the 6 speed. And downshifting in smaller increments on hills to maintain power is where it is going shine. It appears programming on the 8 speed is similiar to the 6 speed in that its designed to never go into the top overdrive gear such as 8 gear. The 2017 truck pulling in 4th (1:1) or 5th (0.83:1) is really no different than 6th or 7th with the 8 speed. Curious as to why the 2020 never used 5th or 4th and the 17 needed 3rd (1.41:1) when both trucks have the same power rating. I wouldn't think the 8 speed was that much more efficient than the 6 speed at putting power on the ground when both transmissions are using this same ratio. Was there some other 'tuning' bits RAM did to the 2019+ trucks?

8 speed Ratios
1) 4.71:1
2) 3.14:1
3) 2.10:1
4) 1.67:1
5) 1.29:1
6) 1.00:1
7) 0.84:1
8) 0.67:1

 

[Sandevino]

The ratios for both transmissions are below.



Aligning the ratios shows the 8-speed has better gearing down low for towing and hauling and nearly equal direct and over-drive ratios.

Both trucks are comparably equipped aside from the transmissions
6.4L Hemi / 3.73 axle ratio / 33" tires / 4x4

The attached transmission mappings are based on the ratios above and theoretical max speeds - clearly no RAM will ever see north of 160mph, but I digress...

 

[wyo2track]

All good information. The trans mapping is fun to look at. Still, I'm trying to understand why the 2017 could not hold 4th which is a 1:1 ratio just like the 2020 in 6th gear. Both trucks at 65 mph would have been turning 2500 rpm. However the '17 needed 3rd gear? I could understand if the 2020 dropped to 5th and the '17 had to grab 3rd. Is there that much of a reduction in parasitic losses between the 6 and 8 speeds?

 

[ronheater70]

I have no doubt the 8 speed is better than my 6. The issues to me is the ones that don't tow much and don't anticipate the terrain. I tow 8800# with another 1500 in the bed. I tow a lot in the mountains of Colorado. I see the terrain changes ahead and manually downshift prior to getting there. Keep the RPM's up and avoid the truck from losing momentum. As far as taking off on a slope. Having hauled heavy equipment (tractor/trailer) in Colorado truckers know not to stop on the uphill side of the mountain when loaded. You can have 1000 ft lbs of torque and your going to have a hell of a time taking off.

Well, I dont think anyone stops on a slope on purpose, Sometimes the situation dictates where you start off from, where you stop at, etc. I have one particular run that was really annoying. That was travelling north on a highway, coming to a stop light and making a 90 degree turn uphill for a good distance from a dead stop. I would have preferred to roll into the exit and keep moving while slowing for a right hand turn and sometimes I pulled it off and it was significantly better experience. But more often than not that dang Light would get us.

 

[RandomRam]

All good information. The trans mapping is fun to look at. Still, I'm trying to understand why the 2017 could not hold 4th which is a 1:1 ratio just like the 2020 in 6th gear. Both trucks at 65 mph would have been turning 2500 rpm. However the '17 needed 3rd gear? I could understand if the 2020 dropped to 5th and the '17 had to grab 3rd. Is there that much of a reduction in parasitic losses between the 6 and 8 speeds?

Wild ass guess: the programming for the 66RFE is to save it from itself by dropping a gear and keeping fluid pumping. I don’t know a thing about the 66RFE, but the quickest way to kill a 700R4 is to lug it with a load as at low RPM not much fluid is circulating and cooling the transmission.

I suspect ZF has figured out a way to keep fluid pumping efficiently at low RPM minimizing heat build up.

 

[sandawilliams]

Well, I dont think anyone stops on a slope on purpose, Sometimes the situation dictates where you start off from, where you stop at, etc. I have one particular run that was really annoying. That was travelling north on a highway, coming to a stop light and making a 90 degree turn uphill for a good distance from a dead stop. I would have preferred to roll into the exit and keep moving while slowing for a right hand turn and sometimes I pulled it off and it was significantly better experience. But more often than not that dang Light would get us.

There are times as you pointed out that a stop is required. Break downs are also a reason to stop on the uphill side. And yes- I see Trailers top on severe inclines often. They are usually out site seeing.

 

[Montessa]

I had a 14' 6.4 regular cab with 4.10's. I pull a 34' race trailer with a lounge stuffed with a 68' Charger. I load a golf cart in the box when running out of town. With all my junk the outfit scaled at 21000. I mostly pull in flat lands and have found the 6.4 6 speed up to the task. Fuel mileage pulling that weight is 7.5 to 8 mpg, 12 to 13 normally. I have got as high as 17 on longer trip empty. I recently bought a 20' regular cab 6.4 8 speed also with 4.10's. I have not pulled the trailer with the 20' due to the Virus. I don't believe that I will see any difference in the fuel mpg however, I am looking forward to the new tranny. On my 14' I found that I was always over riding the 6 speed. It would hang on to the gear to long and get the 6.4 out of it's power range. The same on the take off from a dead stop going up a grade. The tranny would upshift to soon and lug the 6.4 down. With everything being locked down, I don't know when I will get the chance to find out!

 

[sandawilliams]

I manually shift mine anytime there is a change in grade or leaving from a stop- with the trailer hooked up.

 

[olyelr]

I had a 14' 6.4 regular cab with 4.10's. I pull a 34' race trailer with a lounge stuffed with a 68' Charger. I load a golf cart in the box when running out of town. With all my junk the outfit scaled at 21000. I mostly pull in flat lands and have found the 6.4 6 speed up to the task. Fuel mileage pulling that weight is 7.5 to 8 mpg, 12 to 13 normally. I have got as high as 17 on longer trip empty. I recently bought a 20' regular cab 6.4 8 speed also with 4.10's. I have not pulled the trailer with the 20' due to the Virus. I don't believe that I will see any difference in the fuel mpg however, I am looking forward to the new tranny. On my 14' I found that I was always over riding the 6 speed. It would hang on to the gear to long and get the 6.4 out of it's power range. The same on the take off from a dead stop going up a grade. The tranny would upshift to soon and lug the 6.4 down. With everything being locked down, I don't know when I will get the chance to find out!

I think you will find the 8 speed trans to be a huge improvement, not just for towing but dd’ing empty too.

 

[Montessa]

I have a little over a thousand miles on the new truck and have been averaging about 13.5 empty so far. I did pull my trailer a short distance from winter storage. Too short a pull to really make a comparison but the truck seemed happier. This dam virus has everything shut down so, who knows when things will open back up! I am dying to try the 8 speed out on a field trip.