68RFE 6spd auto

[gmctd]

In this thread, I will be detailing the '07.5 Dodge 68RFE 6-speed automatic, incl adding a Transgo shift kit - pics to follow...........

Here's the 6-range 8-class torque-input Rear-wheel drive Full Electronic control six speed transmission - has a separate TCM to handle the shifting chores - drives the large NP27x transfer case

Note the two shaft-speed sensors, input and output - large connector is TCM control - range-selection by cable

Note the line pressure sensor, and large-dia oil cooler pipe connectors

5.9 bolt-pattern and diameter - that large round pie pan is the front cover\seal, covers the dual-range pump

'Nuther shot of the large input shaft

Standard DCJ NP241\271 bolt-pattern, 4wd tailshaft final inspection 335th day of '06, laser etched

Here is the very aggressive 13"dia t\c

Note the four flats to engage the pump drive-gear, and the silicone drive-hub seal

Also, the 68RFE has a larger 'cooler with larger pipes than the 48RE

The pilot diameter in the 6.7 crankshaft is 2.130" while the 5.9 is 1.810" - this means you won't be seeing a 48RE behind the 6.7 for a while, or a 68RFE behind the 5.9 - the t\c-to-flexplate bolt pattern and bolt circle diameter is identical - Suncoast has indicated they will build t\c's as required

tbc................

 

[SEA04DMAX]

looks like a pretty beefy tranny, my bro inlaw just bought a 08 with this tranny.

 

[gmctd]

It's great improvement over the TorqueFlyte 3sp\od 48RE - Dodge also has the Aisin trans, similar in torque capabilty to the Allison - has a stand-alone TCM, allows total manual control of all 6 speeds - part of the cab'n'chassis option, not yet available in the standard-series 6.7 chassis, prolly due to price

 

[duratothemax]

the aisin trans in the dodge is pretty much an allison carbon copy with a japanese name.

 

[gmctd]

The Aisin trans was used in Hino, Mitsu, Isuzu, Iweco, etc medium and HD trucks long B4 DD\Allison released their med-duty version for the DMax, and that was necessary because the 4L80E could not take the torque input of the big Isuzu.

That the Aisin is available in the Dodge c'n'c is prolly one reason MB decided to dump DCJ, as it is not an inexpensive option

 

[duratothemax]

The Aisin trans was used in Hino, Mitsu, Isuzu, Iweco, etc medium and HD trucks long B4 DD\Allison released their med-duty version for the DMax, and that was necessary because the 4L80E could not take the torque input.

That the Aisin is available in the Dodge c'n'c is prolly one reason MB decided to dump DCJ, as it is not an inexpensive option

The AS68rc is a new transmission. The LCT1000 was in development long before it. Allison and aisin have joint ventures in other parts of the world. That aisin trans was designed with an allison blessing. There are several copywrite infringment complaints going on at allison right now as well. It is clutch to clutch, weighs the same as the allison, and has the same internal design. One forward drum with two rotating clutchpacks, and 3 brake clutchpacks. 3 planetaries and PWM TCC control.

ben

 

[gmctd]

The 68RFE is a HD upgrade to the 545RFE used in the Jeep CRD and the Hemi trucks

case: identical but for Cummins bolt pattern
output flange: identical, fits NP24x\27x transfer cases
pan: identical
valve-body: identical
pump: identical but for shaft size
clutches: more clutches per pak
planetaries: one more gear per unit
seals: o.d same, i.d. increased for larger shafts
shafts: all four increased to handle prodigous torque output of the big 6 - stator, input, intermediate, output
torque convertor: CTD gets 13", Hemi and Jeep CRD gets 11"
tailshaft housing: identical, i.d. increased for larger shaft

There no bands or servos requiring adjustment - all clutch-operated planetaries

Transmission Control Module is stand-alone autonomous module with it's own cpu, controls all phases of 68RFE operation, communicates with ECM for torque requirements for any angle of the TPS, rpm

Hemi TCM is integral to the ECM

Jeep TCM is stand-alone with ECM input

 

[gmctd]

The scariest thing about the Aisin is the plastic stator, similar to that in the 545RFE, which disntegrates under the hi-torque output of the Jeep CRD - Suncoast builds a 'billet' tc with a new aluminum stator for the Jeep\Hemi crowd, using the more agressive Hemi tc internals for the Jeep - works wonders for the little mule, eliminates the slush factor

The 545\68RFE is essentially a reduced-torque version of the Aisin, designed in the late '90s for the '99 Jeeps and Dodges, with TCM controlling only 4speeds - requires only a software change to utilize 5spd or 6spd

Be real interested to know if the 68 tc has a plastic stator

 

[Mike L.]

IMHO the 68RFE is a joke. It will not hold power, there are no parts for it at this time. It cannot be beefed up, and it is failing all over. The input shaft will break because of its size. The fix is to convert to the 48RE if you want to hold any kind power.

 

[gmctd]

Be interesting to see links to some of those reported failures, get it from the horse's mouth, as it were - just retired from career of symptomatic failure diagnosis and analysis of events and causes leading to failure - sorta like that kid the Navy blamed for blowing up the gun turret: turned out to be the procedures involving the powder charges - kid was just doing what he had been taught to do - now he rests in peace

 

[Mike L.]

The 545 and 68 have nothing in common with the Aisin. They are basicaly a rear drive oversized 604 transmmision like the Dodge Caravan. They work pretty good behind the hemi but leave a lot to be desired behind a diesel. Suncoast is working on a kit right now, don't know if it's finished yet and they don't have high expectations for the holding power at this time.
Your analysis on the gun turret blowing up indicates you were on the investigating team if I read that correctly.

 

[gmctd]

No - just comparing that well-known incident of failure analysis to my career of when did it start the process of failing, as opposed to just 'fixing' stuff

The 45\545\68RFE is usually compared to 604 because DCJ had nothing else bandless to compare it to, certainly not the Torqueflyte, but the multiple clutched planetary gear train is the future, for now, as noted by all the boxes showing up in that configuration.

Dunno if you're old enuff to remember, but the Torqueflyte didn't have much success behind the Cummins at first, either - some events still require 'billet' shafts in the 618

That's such an abused term, anyway: even standard GE H3 headlamps will sell faster if 'billet' is tacked on in front of them : Billet GE headlamps - 109.95

 

[Mike L.]

The multiple clutch planetary setup is designed for the new torqueless engines everyone is producing now. You see 4 to 5 hundred hp engines producing very little tq or tq at a high rpm. This doesn't set well with a 4 speed auto because there is too much of an rpm drop between shifts and the engine falls off. Hence the 6 and 7 speed close ratio auto's with little rpm drop and motor does not take a dump between shifts. The CummiGs has no need for this. The 68's that I have driven shift so fast they are in 6th before 50mph at full throttle. This shift strategy is to protect the trans IMO.

 

[gmctd]

That's just the difference in 4spds and 6spds in a low-rpm engine, as you indicated - the torque is distributed over more mechanical multiplication - works wonders for towing, tho, just like in the 18-wheelers - I don't notice as much thrust with the NV5600 as with the NV4500, particularly in that wide jump from 2nd to 3rd, but the truck is accelerating just as quickly - just takes some getting accustomed to, with so little rpm range and so many gear ranges

 

[dmaxx3500]

guys will these fit older cslyr engs,like 383.440,and 426 hemis?

 

[gmctd]

Engine flange bolt pattern and dia are different - would need adaptor plate, no hill fer a stepper

 

[gmctd]

'05 48RE input shaft is 1.040"dia across the 23 splines, base shaft is 0.825"dia

'07.5 68RFE input shaft is 1.100"dia across the 26 splines, base shaft is 1.054"dia

Output shaft is 1.425"dia, splined same as the NV4500 and NV5600

48RE is comparable to the 545RFE used in the Hemi trucks, shaft diameters are same, Hemi t\c is 11", uses the NP241 with same input hub as the 48RE

Not much of a 'joke' there, right?

 

[Mike L.]

'05 48RE input shaft is 1.040"dia across the 23 splines, base shaft is 0.825"dia

'07.5 68RFE input shaft is 1.100"dia across the 26 splines, base shaft is 1.054"dia

Output shaft is 1.425"dia, splined same as the NV4500 and NV5600

48RE is comparable to the 545RFE used in the Hemi trucks, shaft diameters are same, Hemi t\c is 11", uses the NP241 with same input hub as the 48RE

Not much of a 'joke' there, right?

Well now that I have been working on this joke of a trans I will tell you this.
There are no parts for it. Valve body's wear out at the acumalator portion and there is no saving it. The valve body is on back order because Dodge cannot make enough fast enough for the failures. The one sided overdrive and underdrive clutches are one sided .050 piece of crap that will burn and warp at anything over 240F.
After numerous attempts by some great transmission companies this trans will never hold more than 450hp on its best day.
This is the same trans behind the 4cyl. Jeep with some whistles.
And you are touting this thing?