6.4 Inching Closer

[Ozymandias]

Power band is different than the CTD, I'm willing to bet "IF" they go with the 8spd auto, it won't be the same.

I expect the same sophisticated programming with the CTD as now with the HEMI.
ZF knows their business.

 

[JR]

.
ZF knows their business.

Agreed. The 8HP truly is an unbelievable unit. I almost daily drive one in a 14 Ram 1500 Hemi, I've also driven one in a Challenger Hemi. Same engines, completely different application. The shift logic is noticable. The 8HP is a work of art IMO.

 

[RVTRKN]

Wishfull thinking, if you were to try to accelerate like the Hemi, the CTD would fall on its face. The problem is the torque management that prohibits the 6.7 SO or HO from, a lack of better words, getting into the throttle.

 

[JR]

Obviously there would be some serious changes in shift logic. To think otherwise would be naive.

 

[fest3er]

To start with, consider the momentum (energy) difference between a 360# crankshaft turning 2500 RPM and a 50# crankshaft turning 4000 RPM.

 

[JR]

The current 8HP is rated for around 750 lb ft, well and above anything it is currently connected to. There have been many variations of this unit over the years, and each variant is rated well and above it's intended duty cycle.

 

[RVTRKN]

History with the 5.9 CTD tearing up transmissions come to mind on this subject. I'm sure the 8spd could be engineered to adapt to the CTD but it wouldn't resemble the same behind the Hemi.

 

[JR]

The difference between Dodge transmissions and ZF is ZF is actually a transmission builder vs an automotive manufacturer. Like Aisin their real bread and butter is HD/vocational segment, albeit with traditionally
longer service intervals and lower cost of ownership compared to Aisin. If ZF offered a unit to mate to a small diesel like the 6.7 I'm fully confident it would be well suited.

 

[ekroman]

I just picked up a 2019 Ram 2500 with the 6.4 Hemi and 8 speed ZF. I’ve only got a few hundred miles on it, but I am impressed. Transmission seems to be on the ball every time.

 

[TFucili]

An interesting tidbit regarding ZF. We have been researching my wife's next ride, and looked at the Honda Pilot. Turns out that one issue that has plagued the later models is the ZF 9 spd, which is apparently used by various manufacturers.

 

[campertruck]

Since this started as a 6.4 Hemi thread I thought I should add in my experience with one. I have a 2016 chassis cab with the 6.4 and the Aisin. The truck has 4:44 gears and it carries a 10 foot slide in camper 95% of the time. I’m approaching 30k miles and so far the truck has performed flawlessly. I average 10 mpg at 65 mph, 11 mpg at 60 mph, and 9 mpg at 70+ mph. The camper is just a block fighting the wind. Empty I get 14 on the highway and 11 around town. My 2006 with the 5.9 Cummins was averaging 11-13mpg with the same camper and 17mpg empty. Here in New England diesel is about $.50 more per gallon so the mileage gain is lost on fuel cost. My brother has 2016 2500 with 6.4 and the 66RFE trans. Comparing them back to back, his shifts smoother and almost seamless and it has MDS so highway mileage is 17-18mpg , local is 13mpg. I feel Aisin is just t right with the gearing. Never in the wrong gear. The 66RFE mated with 3:73 is sluggish at times because it always goes to the higher gear. The 6.4 is very happy at 2000 rpm. I think the new 8 speed will put that engine in the happy zone for sure. I look forward to trying one to see how it goes.