I am not super knowledgeable on this but I do know one difference for you. The R/T’s have a two speed transfer case with Hi/Low range. The SRT’s have a single speed transfer case. That’s about all I can help!

 

Not all R/T's have the two-speed transfer case. Only the R/T's with the factory tow group (non-TnG) have the 2 speed box.

 

Thanks for the info!

I've never seen one on sale here without the hi/lo selector, so I think that's a standard euro spec.

 

The R/T can also be had in rear wheel drive only, which is what I have. The SRT is all wheel drive only, and to me that is a negative. I know plenty of people like AWD (and I get why it appeals to them), but to me its unnecessary weight and complexity. I probably would have shopped SRT when I was looking if it came in a RWD option. On the other hand, the delta between the SRT and R/T was huge and past the point of diminishing returns.

 

After driving RWD and 4×4 vehicles most of my life, i can tell you that the AWD system in my 2024 DD SRT 392 is a gane changer where traction is concerned, and after all, "spinnin' ain't winnin'" , especially during drag race situations. The vehicle does 0-60 in 4.1s and is violent off the line. I tell people to go ahead and put their head against the headrest, before the SRT does it dor them! In low traction situations like heavy rain, it is awesome too and you can feel the extra traction being offered as the drive wheel(s) become the one(sl with the most traction. Therefore, like Audi's Quattro system, you are able to maintain higher speeds and be safe (although any car can hydroplane, of course) and reaction to any scary situations iss definitely quick. I don't feel any "heaviness" or other things negative, only fantastic traction during bad conditions and unbelievable GRIP in dry ones. It truly makes my Durango SRT a true "corner carver" in the N GA mountains and makes it handle better than my Challenger T/A 392 and VERY closely to my ScatPack Charger, if not a little better.

Yes, there are always two edges to ant sword, and the downsides here are reduced fuel economy (due to higher overall friction and weight, but who buys an SRT product for fuel economy) and a little bit increased maintenance (changing transfer case fluids and lubricating everything).

However, given the chance, I would select AWD every time. It makes a big PERFORMANCE difference here and gives the driver thr confidence to push a little further.

Another way that dry condition driving is helped is in cornering, where the system maintains increased traction, a greater emphasis on corner rotation, and the traction to put the massive HP and TQ of the 392 motor down.

Remember, this is SRT BLESSED, so this system is NOT tuned for rock crawling, mud bogging, and other off road adventures. No, like Audi's Quattro system in its S and RS models, it is tuned for performance and to make the Durango QUICKER around a track, through the mountains, down a drawstrip -- or just coming home in a bad rainstorm, where others are scared abd cautious and you're driving right past them. Cautiously, of course. Great system and one that I LOVE in my daily driven 2024 SRT 392 AWD DD.

 

Well in Finnish climate a high power rwd car is a nuissance at best for about a third of the year 😅

 

Especially one with an open differential.

 

They both use the same ZF transmission, 8HP70. The diffs however are not the same. SRT has 3.70 gear ratio, and the rear has electronic limited slip where the R/T has 3.09 gear ratio and the rear diff is open..

 

Transmission on the Hellcat is almost the same, Tuned better an upgraded stronger parts.

 

See if you can find a R/T which has the "Tow N Go" Package"; not to be confused with the standard tow package.

A R/T with the Tow & Go package is essentially a SRT 392 vehicle, except it has the 5.7L motor and 3.09 differential gearing. Everything else (transmission, AWD transfer case, differentials, brembo brakes, bilstein suspension, track/sport/snow/tow drive modes, etc, etc ...) is the same as the SRT. It even gets the fender flares and black rear valence. And the exhaust setup is just perfection as it is.

If you can find one of these, you may be able to get it for a decent price considering most dealers (and individuals) don't really understand the package. If ordered new, it is a $6k upcharge from the factory, and it'll show up on the window sticker as "Tow N Go Package".

Here's what it looks like on my window sticker:

and here's a video demonstrating the OEM exhaust sound from my Tow N Go (this was before any mods):

If you can find one of these, then the drivetrain can already handle at least the power of the SRT's 6.4, since all the driveline components are the same. As an added bonus, you get the stopping power of the 6 piston Brembo SRT brakes and the handling of the electronic Bilstein adaptive suspension.

This is what I did ... bought a 2023 R/T with Tow N Go, then added a Whipple 3.0L supercharger to up the power

I debated on how to add the additional power, and you can read about that decision process here: https://www.dodgedurango.net/thread.../threads/10k-to-bring-r-t-tng-up-to-or-over-392-srt-power-levels.87532/#replies

After I decided on the Whipple, I then documented the install of that here: https://www.dodgedurango.net/threads/3-0l-whipple-install-on-2023-r-t-t-g.88875/

 

I would not call 8HP70 and 8HP95 "the same transmission".

I couldn't locate the source quickly, but I recall reading that they are not directly interchangeable, even though the "crust" is the same. For example the TCUs have different capabilities.

 

... the TCUs have different capabilities.

Interesting ... do you know what the different capabilities are?

I've been studying TCM reads from R/T's, SRT's and Hellcats for a while now, as I learn and make changes to my transmission tuning.

I haven't come across anything available in the 8HP95's TCM which I'm not also finding in the 8HP70's TCM

 

I'm using HP Tuners' VCM Suite software.

The TCM's all have the same shift strategy capabilities, but how the capabilities are configured can be different based on the different models and features.

Shift scheduling has "patterns", and a lot of them:

Then there are tables which allow mapping of driving situations and driver aggression type to those patterns. This is why you can drive aggressively and the tans will shift different for a while, until you go back to driving normally again.

As an example, here is pattern 5 .... which is the standard shift pattern for auto drive mode and a low aggression driver type. The cells in these shift pattern tables hold tail shaft output speed, not engine RPM:

Then when looking at the various clutch control tables (ie: like pressures), there are different shift modes ... Normal (auto mode), Perf (Sport mode), Sport (Track mode), and Max.

Then there are additional control tables which direct the TCM to use a particular mode based on other parameters; mainy which drive mode is selected by the driver. Normal and Perf are available on all HP70 and HP95, Sport (and most likely Max too) are only available on vehicles which have drive modes (R/T with TnG, SRT and Hellcat). But that's really only because the driver has no way to select Sport or Max, not becuase the TCM is any different.

So from the factory, the Hellcat's HP95 may be setup differently to use various modes under different circumstances, or be setup for different shift pattern RPMs and scenario mapping, but the overall TCM capabilities and approaches are the same across the transmissions ... at least, that's been my findings thus far as I learn this.

 

...
So from the factory, the Hellcat's HP95 may be setup differently to use various modes under different circumstances, or be setup for different shift pattern RPMs and scenario mapping, but the overall TCM capabilities and approaches are the same across the transmissions ... at least, that's been my findings thus far as I learn this.

Nice! One must, however, keep in mind that the HPTuners' mapping of the 8HP variant is probably not exhaustive. But again, it would be weird to have differing TCU HW and SW (other than settings) for trannies that are of the same family.

 

Yeah, sometimes HP Tuners gets some mapping incorrect and has gaps. I definitely experienced this with the operating system which came in my 2023 R/T TnG. It took a while to get HP Tuners to acknowledge it and fix it for me. Thy not only fixed some table mappings I knew were wrong, but they also added a couple hundered new mappings which were not included when they initially added support for my OS.

That said, the ZF8 transmissions are widely used across manufacturers and seems to be pretty complete in VCM. I did run across one table which seems to have strange values in it, but HP Tuners support insists it's accurate and correct.

Another interesting thing is the TCM is actually part of the valve body, which makes sense since it's all electronically controlled. The PCM does have some transmission control components in it, and the TCM also has some engine control components in it (ie: TQ mgmt, etc ...), but in general, the TCM mappings seem to be pretty solid.

By comparing my OEM R/T calibrations to those of a stock SRT 392 and to those of a stock 6.2L Hellcat setup, as well as comparing them to what Whipple changed them to in their canned tune ..... I've been able to make mine shift very nicely with the Whipple supercharger installed.

My last adjustment to it was a couple of days ago, and the very next day the wife texted me while she was out running errands to tell me "The transmission is shifting like butter!" She doesn't know when I make changes, but obviously this time she recognized the improvement and appreciated it

Don't get me wrong, it is a very complex setup (bot the PCM and TCM), and I've been working on it since April ... when I did the Whipple install. I went through 3 different tuners, who are all skilled ... who tried to get this right ... but in the end, I just needed to learn it myself if I wanted it to drive like a factory Hellcat does. And dare I say, I've now achieved that

 

Imma dm you for tune file if I get the Durango 😅

 

Haha, sure! Happy to share what has worked for me!

 

I think you may be reading it wrong. I think @ScottDurangoSRT392 means Not all R/T's have the two-speed transfer case. --> Along with the SRT Durango models

I'm just trying to be objective on others thoughts?