It's official! 6.7L: 350/650 and 68RFE

[sag2]

Maybe not, but this rating indicates that the G56 is at it's limit for power. DC should have put in its G65 or G80 (I think those are the model #'s), and not a transmission that is maxed out ... thus proving that the G56 was a pissss poor replacement for the 5600.

And that puff piece in the latest TDR about the G56 was just a marketing ploy.

Hello, the 46, 47 and 48RE were all maxed out! You are not going to put anything bigger than you have to. It's a plain dollars and cents equation.

And really, how many G56 transmissions do you know have failed out of the tens of thousands that have been sold?

 

[FATCAT]

Blah, dude, you are just an old 12v'r that dont like new stuff... :-laf



If you truely need a heftier transmission, you should be looking at a heftier truck.

Why you young wipper-snapper! I bet you have one of them big-screen TV's an them cell-u-ar phones!



And I am looking at used small med-duties ... only problem is insurance and inspections junk when you step up out of lite-duty status.

 

[J&LRam]

a derated Cummins for a manual will put out about the same power to the wheels as a big auto. Some of the aftermarket [BD Power/ATS/etc] found the Allison used about 45-50 hp to operate compared to 20-25 hp for a manual. I don't know what that computes to in torque numbers but I would guess it would be close in auto vs manual numbers at the rear wheels on the new ratings... ... ... JIM

 

[Alphacowboy]

Why you young wipper-snapper! I bet you have one of them big-screen TV's an them cell-u-ar phones!



And I am looking at used small med-duties ... only problem is insurance and inspections junk when you step up out of lite-duty status.

:-laf :-laf No Big Screen, but yes, a Mobile phone is a must when your a self employed construction worker! Hope you didnt take my poke personally, I just love pokin the 12v guys since they seem to be scared of us new electronicly controled diesels!





Also, on the Insurance stuff witht he bigger truck, well, if thats what you use the truck for, you should have the rated vehicle for what you use it for, and if that means higher premiums and lic tabs, and DOT inspections, well, thats the cost of doing business. Personally I hate inspectors, but ya know what, I still have to use them in my field of business.

 

[DPelletier]

Maybe not, but this rating indicates that the G56 is at it's limit for power. DC should have put in its G65 or G80 (I think those are the model #'s), and not a transmission that is maxed out ... thus proving that the G56 was a pissss poor replacement for the 5600.

And that puff piece in the latest TDR about the G56 was just a marketing ploy.

I agree. I have both a G56 and two NV5600's and I think the NV5600 is a stronger, better unit. I won't accept a lower power output for the manual, so maybe my next truck (i'll be buying in the next 12mo) will be an auto for the first time in many years. I wonder why the Aisin is only for the C&C? Why the need for two trannies?



I'm keeping both my NV-5600 trucks, no matter what happens.



Dave

 

[rubberneck]

I keep hearing comments about the 5600 being No doubt stronger than the G56, has anybody broken one of the G56's?? Just curious, cause i dont find a lot about it here on the TDR, and i would think if they were melting down we would see it all over this board. There are plenty of guys on here who have no doubt bombed the heck out of their G56 trucks, anybody had problems??



As far as not being able to do transmission swaps, if there is a demand i think someone will work it out.



And as far as DC phasing out the 6sp manual, that would truly be a sad thing. Im sorry, but a 6speed auto is still not the same as a 6sp manual when towing lots of weight. Autos alway want to downshift and bring rpm up. Our motors pull best down lower in the peak torque.



I agree with klenger, they axe the manual and i'd probably buy the Dmax/ally, or maybe even the ford if it still had a manual. (Ok, well maybe i wouldn't go that low :-laf ) but the dmax would be ok Sad day... ... :{

 

[FATCAT]

:-laf :-laf No Big Screen, but yes, a Mobile phone is a must when your a self employed construction worker! Hope you didnt take my poke personally, I just love pokin the 12v guys since they seem to be scared of us new electronicly controled diesels!





Also, on the Insurance stuff witht he bigger truck, well, if thats what you use the truck for, you should have the rated vehicle for what you use it for, and if that means higher premiums and lic tabs, and DOT inspections, well, thats the cost of doing business. Personally I hate inspectors, but ya know what, I still have to use them in my field of business.

Nothing taken personally :-laf , I'm just an old fart in a 41 yr. old body. I just hate computers controling anything. My 8-5 job doesn't demand any truck, I'm just a weekend worrior with mine doing side jobs. I just like super-overkill in my trucks ... I'd buy a Pete tri-axle if I could just to pull around my 10K trailers ... when I look at new trucks my eye always wonders to the Pete 335, just can't figure it out.

By the way ... I wonder if Paccar will come out with a class 4 or 5 truck.

 

[JJW_ND]

What's up with manual trans....

For 2007 (right now anyway) GM only pairs the auto with their duramax. No manual. Unless Ford changes its current manual trans. , I bet it will be detuned or dropped.



I have been a straight stick guy up until I spent some time in some late model HD dump trucks grossing 70K with 6sp autos. There is no way loaded or unloaded a manual truck would have kept up to those autos. They up shifted and down shifted when needed and held the gear as they were a manual with auto shift.



Im think this auto/manual thing is like brand D versus brand F. Until one tries a new truck with new auto trans, I don't think we are quailified to speak on what the can and can not do.



jjw

ND

 

[rubberneck]

They up shifted and down shifted when needed and held the gear as they were a manual with auto shift.



Im think this auto/manual thing is like brand D versus brand F. Until one tries a new truck with new auto trans, I don't think we are quailified to speak on what the can and can not do.



jjw

ND

True, none of us have driven the new dodge offered 6 speed, but I highly doubt that it is going to perform all that much better than the ally in the new dmaxes, and while they are an absolute kick in the rear empty, they do not work like my 6sp manual when towing period. They like to kick down when you really start working the motor hard. Maybe that has to do with the way the dmax motor makes power. I dont know. Maybe the cummins/dodge set up will let you keep the rpms down and work the thing just like i can with the manual. If they will, I will be one of the first in line. I can have my cake and eat it too so to speak. You are correct, we will have to wait and see. I only wish the dealerships would set a truck up with a goose neck hitch and let us go work these things. Cant tell much driving them around the corner on flat ground

 

[WOT]

Makes me wonder if the derated 6spd manual is due to the transmission or the DMF they currently stuff in front of it?

 

[GButia]

And I thought I was going to get to point out the dmf thing... . dang it! I beleive thats exactly it. An upgraded clutch wil fix that problem. The 6 spd. man. behind the dmax is actually a stout unit once the clutch is upgraded... . the same is probably true of the g56. Also there are plenty of g56 trannys handling mild upgraded power... . just as much as the old transmission in fact... ... so I beleive emissions is your answer to DCs derated hp rating.

 

[HNelson]

It's hard to say why they're derating the 6 speed version. Is it still 350 horse or is it 305 horse like the Chassis engine?



They could derate it because the G56 can't handle it. But could the NV5600 handle it? They never put more than 610 through the 5600 from the factory either, so it's hard to say them not wanting to put more than 610 through the G56 means it's weak.



Maybe they're doing it to save the engine. With an auto transmission you can't go full throttle at low RPM and lug it... . the transmission won't let you, it'll downshift.



Maybe it's emissions related. I'm still trying to think through that one, I can't see how a manual would be worse than an auto in that regards except for the full throttle lugging at low RPM like mentioned above.



Maybe the clutch can't handle it.



Maybe the dual clutch flywheel can't handle it.



Maybe the 305/610 version of the engine is 'heavier duty' and they think the 6 speed manual audience will appreciate that trait rather than trading it for a few more ft-lbs.



Maybe I have no clue?

 

[SEwing]

I would have to say its the clutch. Mine is slipping like a big dog on level 2 of my edge and I don't want to say what it is doing if I put it on level 6. There might also be concerns with the shock that is transmitted through the drive line with a quick change in power, either up or down, without the torque converter to absorb some of that shock. The G56, from what I can tell from the latest TDR magazine is built pretty darn stout but the dual mass flywheel is a terrible idea that D/C should have put some more time in research and development before putting it in these trucks.

 

[rubberneck]

SEwing, thanks for the reply. I have been asking the limits of this clutch and not gotten much feedback, this bums me out. I was just getting ready to buy a juice/attitude for the 06, and was hoping the clutch would survive. How would you categorize your driving style. I drive them like i stole them and that has contributed to the demise of several clutches in the 01. The 06 however is driven by my father who babies them tremendously. He just wanted a little more get up and go for passing and what not. I am hoping with his driving style the clutch will hold, but if not southbend twin disc time it is.

 

[SEwing]

I am getting a SBC Con OFE on Wednesday and I will post how I like it, I will just have to be nice to it until I get it broken in, then I can go back to having fun with the little civics with coffee can mufflers.

 

[KCJackson]

It's hard to say why they're derating the 6 speed version. Is it still 350 horse or is it 305 horse like the Chassis engine?

Interestingly, the press kit only shows the de-rated torque, but doesn't say if the hp is 305 or 350... but...



The caveat is, in order to produce 350 hp at exactly 3013 rpm (as the press kit says), guess how much torque the engine has to be making? You guessed it - 610 lb-ft at 3013 rpm. So there could be a 350/610 rating - that would imply one hellaciously flat torque curve (1400 rpm all the way to 3000) - and the G56 and/or its clutch/DMF cannot take more than 610.



The chassis-cab is going to see more potential abuse by its drivers (the "not my truck" attitude), so the power/torque drop off makes more sense in that application.



My guess is the G56 would get the 305/610 rating... as January gets closer, they'll update the data sheet.

 

[MAshley]

How much power and TQ do we really need????????



I have a 06 G56 and i cross the scales at just under 26K. In first gear . . loaded mind you I can still feel the rear tires slip on dry pavment when I put my foot into it... ... dully no less. So as far as I can tell I have all the power I need. I agrea derating a manual is interesting, but we also have to remember that there a 1000's of people buying this truck that no very little about driveing and all about using the skinny peadle until something breaks, the way I see it, its for warentee issues, plane and simple. to much TQ and power at the wrong time,,,,, and your going to make a cork screw out the the drive line.

 

[FATCAT]

How much power and TQ do we really need????????

Do you really mean to ask that question around here? I'm sure if Dodge was puting out 600/2150tq with a Super-18 there would still be folks (probably like me) saying "why not 700hp/2500tq!!!".



I wonder if a FSO-8406 would bolt up to the new Dodges?

 

[amsoilman]

HERE'S your ANSWER!



NV5600 6 Speed Specifications:



Case:... ... Cast Iron

Bellhousing:... ... Aluminum Alloy

Torque Rating:... ... 550 lb. -ft.

Gross Vehicle Weight:... ... 16,000 lbs.

Gross Combined Weight:... ... 26,000 lbs.

Transmission Weight:... ... 360 lbs.

First Gear Ratio:... ... 5. 63-1

Second Gear Ratio:... ... 3. 38-1

Third Gear Ratio:... ... 2. 04-1

Fourth Gear Ratio:... ... 1. 39-1

Fifth Gear Ratio:... ... 1. 00-1

Sixth Gear Ratio: . 073-1... ... (Overdrive)

Reverse Gear Ratio:... ... 5. 63-1

Oil Capacity:... ... 9. 5 pints

Oil Capacity with optional filter:. . 10 pints

Recommended Lubricant:..... Texaco STF

Input Shaft:. . 10 Spline, either 1. 25" or 1. 375"

 

[DPelletier]

We've seen all that before, Wayne. The NV5600 has proven itself at far higher torque levels than that for YEARS. Maybe the aluminum cased G56 is a decent transmission and the reality is that it has been holding up well, BUT the NV5600 needs no further endorsement and I'm not a fan of the DMF. Sure you can replace it, but why should you have to bother on a brand new truck?

Sorry, still an NV5600 fan.



As far as the other issue goes, who knows why they derated the manual. Could be for many reasons (clutch, DMF, transmission, torque management programming, etc. ) but I don't CARE why. I guess my next truck will be an auto. It's too bad, really.



Dave