Then there was four- digits of torque.

[Randomrunner12]

Who knows these days. They should spend money on building better roads first lol.

 

[CUMMINZ]

I stand by my original comments several years ago as I do now. Until we experience an 8-10 speed behind a 6.7 cumminz none us truly know what that experience will be. Anytime you can do a better job keeping a diesel in the middle of the TQ range the better it will perform. Lets all remember what a difference it made when we went from a 4 speed to a 6 speed.

 

[CUMMINZ]

Every test I have seen with the ten speed GM and Ford where they are pulling anything substantial, they are always in 6th or 7th anyway. Half the time they can't even pull in direct, so what good do the extra gears do, other than rolling around empty. Is it an improvement? Maybe. Game changer? Not in my eyes.

Lets remember you are not always in a tuff pull. Once you get on flat ground running 75 you will enjoy those 3 extra gears.

 

[Wiredawg]

Lets remember you are not always in a tuff pull. Once you get on flat ground running 75 you will enjoy those 3 extra gears.

I'd love to have two more gears on my 5500 with 4.88s. Pulling is fantastic, but solo would be better. Even closer spacing and 8 would be great.

Cheers, Ron

 

[Cummins12V98]

So on these 8-10 speeds are the final gear ratios higher than the 6 speeds with the same rear gearing?

The 4 speed would have been "OK" if there wasn't such a big jump between 3 and 4.

Just don't see that much of a benefit 6-8 or 6-10 with a CUMMINS, now gasser for sure!

 

[NIsaacs]

I think on top they are about the same, just lower on the bottom and more in the middle.

I think you are backwards on the gasser/Cummins. The gasser has rpm off the charts, not so with Cummins.

 

[Wiredawg]

So on these 8-10 speeds are the final gear ratios higher than the 6 speeds with the same rear gearing?

The 4 speed would have been "OK" if there wasn't such a big jump between 3 and 4.

Just don't see that much of a benefit 6-8 or 6-10 with a CUMMINS, now gasser for sure!

Ron, I correlate it like this.... 18 wheelers are running 12 and 15 speeds for 80K LBs, and our trucks as high as 43KLbs. The big rigs try to keep as little variation in RPM as possible to keep the truck in the sweet spot. Having 2 to 4 more gears spread evenly could get maybe a slight bit better fuel mileage.

My wifes 1500 has an 8 spd that i believe helps it get a mile or two a gallon better. And even more seamless shifting.

The debate can go on, but competition, technology, and efficiency are ALWAYS going to drive and win the market.

That's how I see it.

Cheers, Ron

 

[Cummins12V98]

So once cruising mileage will be the same. Pulling a grade you may get the in between gear that may hold a couple mph faster up the grade.

The ford trans temp was running 220 that is NOT going to add to longevity. Looking back so far the worse I have seen was 100 ambient, 178 trans locked in 3rd on a long grade. The TFL test was done in cold temps.

If we are going to loose the AISIN that's another reason to keep my truck.

 

[Wiredawg]

Ron,

I'm with ya, I vote to not install a Ford transmission or engine in a Ram. I'm sure Aisin or equivalent will build one that performs to our strict standards. I don't know about you, but my 5500 is my last tow rig as I expect the longevity and toughness will outlast me.

Cheers, Ron

 

[kthaxton]

I think on top they are about the same, just lower on the bottom and more in the middle.

Agreed. Lower gear(s) at the bottom, and closer ratios throughout. They can't really add to the top end unless they start using lower axle ratios across the board.

 

[Ozymandias]

Agreed. Lower gear(s) at the bottom, and closer ratios throughout. They can't really add to the top end unless they start using lower axle ratios across the board.

Correct, the axle ratio will be lower because of the lower gears they add, and that safes also fuel.

Best for fuel economy would be a 1:1 in tallest gear transmission and a 2.80 something axle ratio.
Thats how the big trucks are geared, an Overdrive transmission costs fuel.

 

[AH64ID]

The other thing about the Class 8 is they have a much smaller usable power band than we do on these "little" diesel, so they have to have more gears to get the job done.

Yes the 10R140's top gear is nearly identical to the 68/AS top gear. 0.63, so it won't do any good for the 4.10, or 4.88, crowd. The ultra low 1st gear does really reduce the need for 4.10's thou, especially 4.88's.

1st gear on the 10R140 with 3.42's is geared at 15.78:1
1st gear on the AS68RC with 4.10s is geared at 15.3:1

So the Ford trans is geared lower in 1st than an Aisin and 4.10's.


Funny about the Ford trans running hot, as it now has a 150K miles fluid service interval for normal or severe service. Apparently Ford doesn't care about the temp.

 

[Cummins12V98]

I tow heavier than most and on the West Coast. At 35k combined on even steep grades on launch it simply takes off with zero shudder or hesitation.

I agree on the tight power and of the big boys.

 

[Cummins12V98]

Personally would never go 150k if towing the weights I do.

 

[CUMMINZ]

This is not about getting up the grade faster. It is about doing it more effortlessly therefore more economical. Plain and simple. If you launch easier, cruise easier at lower RPM at top end and the 8 or 9 gears in the middle closer together. That keeps you in the power curve more.

 

[Wiredawg]

This is not about getting up the grade faster. It is about doing it more effortlessly therefore more economical. Plain and simple. If you launch easier, cruise easier at lower RPM at top end and the 8 or 9 gears in the middle closer together. That keeps you in the power curve more.

Well said! And with the current high and increasing GCWRs too. And quick side comment: There are only a couple folks on the TDR I'm aware of that are even running at or above the GCWRs of 38.5K their 4th Gen trucks and no one on a 2019+ running at the 43KLb GCW.

I just checked the fuel log on my former 09 4500 (4.44s) and compared to my current 17 5500 (4.88s). Both trucks approximately 98% heavy towing duty cycle almost 34KLbs GCW, and both 112 gallons fuel.

09 4500: 9yrs, 69Kmiles; avg 9.559MPG; Best tank: 13.967MPG; Worst tank 4.915MPG
17 5500: 2yrs, 19Kmiles; avg 9.444MPG; Best tank: 13.275MPG; Worst tank 7.022MPG

EDIT: My point is more or less against myself...basically, I haven't lost significant MPG (.692MPG) basically losing my overdrive on the 17 with the 4.88s versus the 4.44s on the 09. Still, 7 tenths of a MPG over time would add up.

EDIT-EDIT: Sorry to do it again, but better comparison isn't the two best tanks, but the actual averages, which is only .115 MPG less on my 5500 than on my 4500. Almost insignificant.

It's hard to say if an 8 or 10 speed transmission would improve these numbers, but I'm thinking there will be a small improvement just for being in a little better RPM for the load/grade. Anyhow, we'll see what Ram does AND we'll see how those Fords hold up with those 10 speeds.

Cheers, Ron

 

[Jim W]

I am extremely happy the 68RFE and it has been very reliable to me and I see no reason for an 8 or 10 speed transmission. I can run all day long at 65 to 70 MPH around 1,600 to 1,700 RPM's towing my 5er on the interstate. The TQ curve on the engine with the gear ratios of the 6 speed are matched will and provide all the necessary power to the ground as needed.

I like to keep the engine RPM's around 1,500 to 1,800 and the transmission seem to do this very well, until it wants to shift to 5th or 6th gear at 45 MPH. Than the engine will drop to under 1,200 RPS's so, I lock out 5th and 6th until I am on the highway. An 8 or 10 speed would be worse in my opinion unless the trans is design to be very closely geared to prevent lugging! The only reason I can see an 8 or 10 speed is it to keep up with the Jones in a marketing war.

Has I sated in my previous comment and I quoted part of the statement again. The TQ curve on (at least my engine) the Cummins is fairly will matched to the 6 speed of the 68RFE. Now I tend to stay in the 1,500 to 1,800 RPM range and the trans shifts well with no hesitation. I can get my load moving with very little throttle input. In fact, I need to step on the brake when moving extremely slow if I am trying to position my trailer.

Now if the TQ curve has change sufficiently to warrant a new 8 speed or 10 speed I am open to changes. But I do not think the TQ curve has changed that much from the 350 HP engine.

I do not see the benefit of more gears just to satisfy the market place of advertising an 8-10 speed transmission. Especially if I can cruise in 6th gear at 1,600 RPM's doing 65 MPH towing my trailer, I do not need to go 75 or 80MPH when towing.

 

[Ozymandias]

Well, some want to go 90mph.
Just go to Wyoming, the majority on the road goes that speed, with and without trailer. At 65 you'd be a road block there.
And think about the massive increasing trailer weights since your truck was built. Thats sure a strong point for an 8 speed.

 

[TFucili]

Well, some want to go 90mph.
Just go to Wyoming, the majority on the road goes that speed, with and without trailer. At 65 you'd be a road block there.
And think about the massive increasing trailer weights since your truck was built. Thats sure a strong point for an 8 speed.

I have towed across Texas where the speed limit is 80, and I stay in my 65-68 mph range. They can pass me all day long.

 

[Cummins12V98]

Well, some want to go 90mph.
Just go to Wyoming, the majority on the road goes that speed, with and without trailer. At 65 you'd be a road block there.
And think about the massive increasing trailer weights since your truck was built. Thats sure a strong point for an 8 speed.

If the final drive is the same what does the 8-10 speed have to do with it? 3.42's with AISIN are the best of both worlds. If they were still available that is what I would order.