My New 2019

[RVTRKN]

The trans downshifts real firm when braking hard, but its soft if lightly hitting brakes. I'm realy liking it so far, the only downside is not exorcising the EB. The upside is the shifting points are are lot higher and won't shift up when cruising at lower speeds. In other words, I don't have to lock out 5th and 6th when driving under 50 MPH. That was the most aggravating thing I hated with the 68rfe I drove for awhile, it would shift into 6th at 50/55 MPH, if I had it in T/H it would clunk real bad shifting at times. Aisin and T/H is almost like a manual transmission down shifting, but keeps RPM's up and out of the wrong gear when accelerating. I run the EB with T/H, when on the hi-way and EB off in city driving.

 

[AH64ID]

I have yet to think my Aisin is in the wrong gear without TH on. It never lugs, short shifts, or holds onto a gear too long. TH when empty is often the wrong gear thou, as it just doesn’t need the rpms it’s holding. My EB is usually on, but not always.

 

[RVTRKN]

If you like low RPM's in "Drive" and T/H off, then thats what you'll chose. For me, I like my RPM's to be where the CTD was designed to be in, and for power when asked for. Mine will not lug as bad as the 68rfe I drove for awhile, but it runs below the power range of the CTD. Mine does have the 3:73, which helps. To each his own, but I prefer the power range when driving a CTD. The 68rfe is another story, I didn't like it in any configuration, but the 3:42's were part of the issue.

 

[AH64ID]

If you like low RPM's in "Drive" and T/H off, then thats what you'll chose. For me, I like my RPM's to be where the CTD was designed to be in, and for power when asked for. Mine will not lug as bad as the 68rfe I drove for awhile, but it runs below the power range of the CTD. Mine does have the 3:73, which helps. To each his own, but I prefer the power range when driving a CTD. The 68rfe is another story, I didn't like it in any configuration, but the 3:42's were part of the issue.

The 6.7 is not a 5.9, and thus has a different power band. These rpms are way too low for a 5.9, but not a 6.7. HP is rated at a lower rpm, and governed speed is also a lower rpm. Peak torque rpm is up a little, but then again it’s up to 50% more torque than a 5.9 so it’s hard to really compare that. I’ll bet it makes 5.9 torque levels 200-300 rpms sooner, or more.

The increased displacement and the variable turbo are huge factors in lower rpm operation.

Running lower rpms is what the 6.7 likes and does well, and is running as designed at lower rpms especially when empty.

It’s all part of the reason I’m very surprised they dropped 3.42’s. 3.73’s just aren’t needed, and based on trans gearing will have negative effects towing around 65-70.

 

[JR]

. The 68rfe is another story, I didn't like it in any configuration, but the 3:42's were part of the issue.

Didn't your OEM G56 require thousands in upgrades at very low mileage?

The 68 isn't an issue in any part of the equation or configuration no matter how many times you claim it.

 

[RVTRKN]

I disagree with most of what you posted. The programing is where the 6.7 gets its HP, not the displacement and longer stroke. Actually, it makes it worse, a shorter stroke adds power, not less. So the bigger displacement helps it overcome the longer stroke. There is a reason that Cummins went to a bigger displacement, it reminds me of the early smog requirements that restricted smaller V8's in the 70's, they went to a larger displacement to try to gain the HP lost. When the 6.7 was introduced, it purpously juiced up the power to stay ahead of the compition. If the Diesel wars, that are still ongoing, weren't effecting the market, the 6.7 introduction would have been a little closer to the 305 HO in the early common rail CTD. Driving a longer stroked engine at a lower RPM is not effecient, and is why I keep it IN THE POWER RANGE of the CTD, so I will keep my practice of keeping the shifting range between 1600 to 1800 RPM, not 1200 to 1400 RPM.

 

[RVTRKN]

Yup, it sure did, and is a big reason why I cursed myself for not opting for the Aisin in the first C&C's, I realy missed the NV5600, and is why I wanted a manual.

Didn't your OEM G56 require thousands in upgrades at very low mileage?

The 68 isn't an issue in any part of the equation or configuration no matter how many times you claim it.

The 68rfe I drove did cause a lot of aggravation for me in any mode I drove it in, no matter what your opinion is, it didn't change the fact that it would run at 1000 RPM when in drive at lower speeds.

 

[TFucili]

Well, I will fiddle with it a bit more, but I ran T/H for my morning routine. Through town here the speed limits range 35-45, except for some 25 areas where there are pedestrian areas, and I find it runs more RPM than I like, pushing 1800-2000 RPM when empty even going downhill. Then, as soon as I started braking, not heavy braking, to make the turn onto my street it quickly dropped to second and spun up to about 2700 RPM. It's a preference thing, I understand, but I don't care for that. I will admit the non T/H programing may be a little too eager to grab 6th and lug along at 1000 RPM in some circumstances, but I prefer running without T/H and with EB on. I will experiment some more, but that's the quick take.

 

[AH64ID]

Hardware has to allow for programming. You can’t program what the hardware won’t allow. Well you can, it just won’t run well.

The reason for larger displacement is irrelevant to how larger displacement engines operate vs smaller displacement ones. More displacement and a longer stroke makes for more low rpm potential, as evidenced by the 5.9 vs 6.7.

Shorter strokes allow for higher rpm operation due to piston speed/acceleration. That’s part of why the 5.9 is a higher rpm engine, but only part. It doesn’t mean you’ll get more power just from a shorter stroke, just more high rpm potential for power... then again the higher the rpm the less tq per hp.

Longer strokes engines are certainly more efficient at lower rpms, obviously to a point. When empty TH reduces my commute economy by at least 1mpg, more when it’s cold out. The engine just isn’t as efficient at the higher rpms. You can watch the instant readout at a constant speed and just go from 6-5 and 5-6, 6 gets the best economy even with the rear wheel torque loss of the taller OD.

Your truck shifts at 1200-1400 in non-TH? My sure doesn’t, shifting is closer to 1600-1800 in non-TH and above 2K in TH.

 

[RVTRKN]

I'll double check the RPM's, but what style of driving are we talking about. If you drive it like grandma, then the longer stroke is in your favor. I don't Ricky race everywhere, but I sure don't like to get behind grandma. 1MPG is not that much to worry about, I'll take the less MPG over dogging of my CTD.

 

[Newsa]

By definition, lugging in diesel terminology and with existing programming means when you press the accelerator pedal, the truck does not speed up.

In my experience, when unloaded & not towing, 1000 rpm's is not lugging it in any gear. Maybe my torque management is WAY different at 1000-1200 rpms?

 

[Wiredawg]

I've been reading opinions about the Aisin and lugging the engine.

I know my engine has a different cam, power band, but my transmission never let's my engine LUG. I checked last week driving my truck and transmission in normal mode, was in 6th locked at 42 MPH. Lugging is when engine is strained and when pressing accelerator, engine doesn't respond. My engine has NEVER lugged.

On my truck, power band gets max tq at 1600 RPM and MaxHP at 2400 RPM. The engine and trans are happy unloaded to run below 1600 RPM.

What I'm reading is more about personal taste in where the owner wants to operate RP wise. I don't care and only paid attention recently because of discussion on the TDR.

EDIT: Just though I'd add the only time I manually shift the transmission down is going down extreme grade at full load to get max engine braking... all the other times transmission decides. TH only when towing heavy. On the C&Cs, EB stays selected on at every startup, so don't have to ever touch that, unless we ever get ice.

There's really no wrong answer on this subject. just like all the other topics.

Enjoy and Cheers,

Ron

 

[AH64ID]

I'll double check the RPM's, but what style of driving are we talking about. If you drive it like grandma, then the longer stroke is in your favor. I don't Ricky race everywhere, but I sure don't like to get behind grandma. 1MPG is not that much to worry about, I'll take the less MPG over dogging of my CTD.

Regular driving? But your regular is likely different than my regular. I wouldn't say I drive like a grandma, but I'm also not riding the bumper of the guy in front of me.

1 mpg may or may not break the bank, but the point is that TH makes the motor less efficient when empty. I've never messed with loaded numbers, but I'll bet that it's not as much of a difference.

Still not sure why you think it's dogging the engine. Cummins would disagree with that statement.

I've been reading opinions about the Aisin and lugging the engine.

I know my engine has a different cam, power band, but my transmission never let's my engine LUG. I checked last week driving my truck and transmission in normal mode, was in 6th locked at 42 MPH. Lugging is when engine is strained and when pressing accelerator, engine doesn't respond. My engine has NEVER lugged.

On my truck, power band gets max tq at 1600 RPM and MaxHP at 2400 RPM. The engine and trans are happy unloaded to run below 1600 RPM.

What I'm reading ismy about personal taste in where the owner wants to operate RP wise. I don't care and only paid attention recently because of discussion on the TDR.

There's really no wrong answer on this subject. just like all the other topics.

Enjoy and Cheers,

Ron

Yes personal preference is just that.

You are dead on by saying the AISIN won’t let the engine lug and that’s 100% correct. You couldn’t lug a 6.7 with and AISIN if you tried.

If some like more rpms then that’s fine, just want to be sure we’re not confusing personal preference with better for the engine.

 

[TFucili]

It's a bit odd sometimes. I turn east on US60 off my street, and it's probably a 2-3%(guessing) downgrade, and this truck will usually march right up to 6th at about 30-35 mph, but some days, unrelated to ambient, coolant, or trans temperature, it will get up to 4th and just hang there, going downhill, mind you. Same speeds, same application of the foot feed. Conversely, I can start downtown and go west on US60, even from a dead stop at the light by the BNSF overpass, and there is an initially fairly steep grade beginning where you go under the railroad, and this thing will consistently march right up to 6th at 30-35 and about 1000 RPM, uphill. The day I came back from having it re-flashed I descended Yarnell Hill, roughly 1800 feet elevation change and lots of sharp bends, easing on down with the EB, and I exited the last fairly sharp bend in 5th, and got into the left sweeper where you can accelerate into the 65 mph zone, and it just hung in 5th refusing to upshift. I was going downhill at over 60. I finally let off, let the EB come on for a few seconds, and then got back on it pretty hard, and it finally grabbed 6th. This is not a complaint, BTW, but "the little man in the box" sure does seem confused sometimes.

 

[Newsa]

Yes personal preference is just that.

"To be sure we’re not confusing personal preference with better for the engine".

I especially like this statement above.

 

[RVTRKN]

I'll double check the RPM's, but what style of driving are we talking about. If you drive it like grandma, then the longer stroke is in your favor. I don't Ricky race everywhere, but I sure don't like to get behind grandma. 1MPG is not that much to worry about, I'll take the less MPG over dogging of my CTD.

1500 to 1800 in the first two gears, its 1500 to 2000 RPM in the medium gears,. It will settle at around 1800 RPM in a cruising speed in 5th band waiting for acceleration beyond 2000 for 6th. I didn't get to 6th because of the short trial run.

It's a bit odd sometimes. I turn east on US60 off my street, and it's probably a 2-3%(guessing) downgrade, and this truck will usually march right up to 6th at about 30-35 mph, but some days, unrelated to ambient, coolant, or trans temperature, it will get up to 4th and just hang there, going downhill, mind you. Same speeds, same application of the foot feed. Conversely, I can start downtown and go west on US60, even from a dead stop at the light by the BNSF overpass, and there is an initially fairly steep grade beginning where you go under the railroad, and this thing will consistently march right up to 6th at 30-35 and about 1000 RPM, uphill. The day I came back from having it re-flashed I descended Yarnell Hill, roughly 1800 feet elevation change and lots of sharp bends, easing on down with the EB, and I exited the last fairly sharp bend in 5th, and got into the left sweeper where you can accelerate into the 65 mph zone, and it just hung in 5th refusing to upshift. I was going downhill at over 60. I finally let off, let the EB come on for a few seconds, and then got back on it pretty hard, and it finally grabbed 6th. This is not a complaint, BTW, but "the little man in the box" sure does seem confused sometimes.

Are you in T/H? What your describing is why I leave it in T/H

Yes personal preference is just that.



If some like more rpms then that’s fine, just want to be sure we’re not confusing personal preference with better for the engine.

So you think running at 1500 to 1800 in all gears vis more harmfull.

 

[Wiredawg]

I didn't want to keep editing my post above and wanted to add another point: With the incredible GVWR and GCWR plus amazing HP and TQ, the transmission has VERY LITTLE slippage, that can make for VERY FIRM shifts, especially low speed downshifts. One time pulling 5er to turn in at dealer, it sounded/felt like it SLAMMED pretty hard as making a turn up pretty step grade, I got off the accelerator and back on it, down shifted hard, and then upshifted pretty hard. I think the slam is just the programming not allowing slippage where if it did, would create heat and wear.

I'm not a transmission guy, and I could be wrong, but this is MY opinion about the slamming on 1 to 2 and 2 to 1 shifts. Its an aggressive transmission designed to carry and pull heavy loads. For my part, I like that its almost bullet proof.

Cheers, Ron

 

[TFucili]

My experience in T/H is it will make it hang in a lower gear even longer when you are basically able to coast downhill. I don't care for that. This is when empty, BTW.

 

[Newsa]

I didn't want to keep editing my post above and wanted to add another point: With the incredible GVWR and GCWR plus amazing HP and TQ, the transmission has VERY LITTLE slippage, that can make for VERY FIRM shifts, especially low speed downshifts. One time pulling 5er to turn in at dealer, it sounded/felt like it SLAMMED pretty hard as making a turn up pretty step grade, I got off the accelerator and back on it, down shifted hard, and then upshifted pretty hard. I think the slam is just the programming not allowing slippage where if it did, would create heat and wear.

I'm not a transmission guy, and I could be wrong, but this is MY opinion about the slamming on 1 to 2 and 2 to 1 shifts. Its an aggressive transmission designed to carry and pull heavy loads. For my part, I like that its almost bullet proof.

Cheers, Ron

Pretty amazing that the rest of the drivetrain doesn't suffer because of a slamming transmission. My wife would not tolerate that type of aggressive shifting just as she does not tolerate any other agressive driving

 

[AH64ID]

1500 to 1800 in the first two gears, its 1500 to 2000 RPM in the medium gears,. It will settle at around 1800 RPM in a cruising speed in 5th band waiting for acceleration beyond 2000 for 6th. I didn't get to 6th because of the short trial run.

TH or non-TH?

Based on the conversion above I presume non-TH, just want to be clear.

That's about how mine shifts in non-TH. All less than 2000, which is fine by me.

So you think running at 1500 to 1800 in all gears vis more harmfull.

Not harmful at all. I think running it at more rpms than required isn't beneficial.