2018 Jeep Wrangler (JL) 2-Door Spied, ZF 8-Speed Auto and Other Details Confirmed!

[The Great Grape Ape]

Regarding the manual w/ the diesel, doesn't the Ram 2500 offer that combo? Granted that's a different class but at least it's not unheard of. A guy can dream right.

Yep, it does, but it's big and heavy. And suprisingly even then it's not capable of full Cummins torque, even the 8 speed auto isn't an option just two 6-speed autos (both of which significantly best the 8HD90, let alone the 8HD75), with the mid level offering being the Chrysler 68RFE and for full torque it must go to the Aisin AS69RC for the full 900+ lb/ft the Cummins can offer. So yeah, even when they do put the manual in the Ram it has to give-up about 150-250lb-ft to the automatic options. However, yeah it would be able to handle the Ecodiesel in a Wrangler, it's just big & heavy, two things not fitting for the Wrangler.

Check out this other thread where we touched on it a bit (got to the next page [4] for more about the torque-transmission issue)
http://www.jlwranglerforums.com/for...mule-spied-with-def-tank.116/page-3#post-3739

As I mention, it's all doable, just seems like an unlikely combo with the manual and full power diesel, but a detuned ecodiesel with ~500 NM of torque would likely work well with the 'possible' Tremec 3160 and still be very well received even if it gve back a few dozen torx to make it happen.

One of the biggest issues/challenges against FCA offering that combo IMO is that if it needs to be de-tuned in any way to fit under some torque restrictions it becomes a warranty repair issue if customers are in any way able (not only allowed) with flash units to adjust the tune and boost the power well outside of the handling capabilities of the transmission. The ZF 8-speed 8HD75 they plan on using could handle a +125ftlb/170NM tune and still be under spec, so it offers them a huge buffer for people tweaking and for maturation of the stock engine also.

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[JCC]

Yep, it does, but it's big and heavy. And suprisingly even then it's not capable of full Cummins torque, even the 8 speed auto isn't an option just two 6-speed autos (both of which significantly best the 8HD90, let alone the 8HD75), with the mid level offering being the Chrysler 68RFE and for full torque it must go to the Aisin AS69RC for the full 900+ lb/ft the Cummins can offer. So yeah, even when they do put the manual in the Ram it has to give-up about 150-250lb-ft to the automatic options. However, yeah it would be able to handle the Ecodiesel in a Wrangler, it's just big & heavy, two things not fitting for the Wrangler.

Check out this other thread where we touched on it a bit (got to the next page [4] for more about the torque-transmission issue)
http://www.jlwranglerforums.com/for...mule-spied-with-def-tank.116/page-3#post-3739

As I mention, it's all doable, just seems like an unlikely combo with the manual and full power diesel, but a detuned ecodiesel with ~500 NM of torque would likely work well with the 'possible' Tremec 3160 and still be very well received even if it gve back a few dozen torx to make it happen.

One of the biggest issues/challenges against FCA offering that combo IMO is that if it needs to be de-tuned in any way to fit under some torque restrictions it becomes a warranty repair issue if customers are in any way able (not only allowed) with flash units to adjust the tune and boost the power well outside of the handling capabilities of the transmission. The ZF 8-speed 8HD75 they plan on using could handle a +125ftlb/170NM tune and still be under spec, so it offers them a huge buffer for people tweaking and for maturation of the stock engine also.

Great rundown, thanks!

 

[JCC]

Sorry for the duplicate reply.

 

[Indio]

Yep, it does, but it's big and heavy. And suprisingly even then it's not capable of full Cummins torque, even the 8 speed auto isn't an option just two 6-speed autos (both of which significantly best the 8HD90, let alone the 8HD75), with the mid level offering being the Chrysler 68RFE and for full torque it must go to the Aisin AS69RC for the full 900+ lb/ft the Cummins can offer. So yeah, even when they do put the manual in the Ram it has to give-up about 150-250lb-ft to the automatic options. However, yeah it would be able to handle the Ecodiesel in a Wrangler, it's just big & heavy, two things not fitting for the Wrangler.

Check out this other thread where we touched on it a bit (got to the next page [4] for more about the torque-transmission issue)
http://www.jlwranglerforums.com/for...mule-spied-with-def-tank.116/page-3#post-3739

As I mention, it's all doable, just seems like an unlikely combo with the manual and full power diesel, but a detuned ecodiesel with ~500 NM of torque would likely work well with the 'possible' Tremec 3160 and still be very well received even if it gve back a few dozen torx to make it happen.

One of the biggest issues/challenges against FCA offering that combo IMO is that if it needs to be de-tuned in any way to fit under some torque restrictions it becomes a warranty repair issue if customers are in any way able (not only allowed) with flash units to adjust the tune and boost the power well outside of the handling capabilities of the transmission. The ZF 8-speed 8HD75 they plan on using could handle a +125ftlb/170NM tune and still be under spec, so it offers them a huge buffer for people tweaking and for maturation of the stock engine also.

So the ZF 8-speed automatic transmission to be used with the petrol V6 engine is the 8HD75? Searching the web for that model number, I am not finding much. Maybe it is a new version? Sounds like you think the 8HD75 will be up to the task in terms of strength and then some? Do any current variations of it have a good track record in terms of strength and longevity? Over the years Jeep has used some good and not so good transmissions. Hoping the ZF 8-speed auto in the new Wrangler is a strong and dependable transmission. I feel like if a complex 8-speed trans goes south that could be a large repair bill. I remember back in the day pulling the C4 3-speed auto trans out of my 1965 Mustang and having it rebuilt for $125, lol.

 

[Milous]

So the ZF 8-speed automatic transmission to be used with the petrol V6 engine is the 8HD75? Searching the web for that model number, I am not finding much.

850RE

 

[The Great Grape Ape]

So the ZF 8-speed automatic transmission to be used with the petrol V6 engine is the 8HD75?

Sorry, that shoulda been HP, with writing all the 1500 HD etc, it just got switched around when I typed it.
But it's doesn't seem to be destined for the petrol engine, just the diesel, like in the Grand Cherokee.
The 8HP75 is the higher torque model of the second generation ZF transmissions, the mid-range torque version scheduled for the petrol engine is the 8HP50. For chrysler it will likely follow previous models in getting it's own name as mentioned by Milous the 850RE as the 8HP45 was the 845RE and the 8HP70 was the 870RE, and the Mercedes W5A580 become the current NAG1 in the JK. The lineup is called called the "TorqueFlite 8" in the FCA stables which recycles an old name for a well know/respected transmission lineup from Chrysler's past.

I do wish they put the 8HP75/875RE in some of the gasoline versions to allow for future upgrade like Hemi swaps or forced air induction, but it seems destined solely for the diesel, although I could ne wrong and maybe it becomes another Rubicon/Sahara differentiator similar to the D44s on the current JK lineup.

Sounds like you think the 8HD75 will be up to the task in terms of strength and then some? Do any current variations of it have a good track record in terms of strength and longevity? Over the years Jeep has used some good and not so good transmissions. Hoping the ZF 8-speed auto in the new Wrangler is a strong and dependable transmission. I feel like if a complex 8-speed trans goes south that could be a large repair bill.

Yeah, the ZF transmissions are pretty solid, and appear on a bunch of platforms from Jeep, Ram, BMW, Porsche, Bently, Range Rover, etc. Their top of the line 8HP90 is inside the hellcat. Every transmission has its issues, even the NAG1 as a W5A580 had issue with water on early models, but has done well since, the ZF though has aquited itself pretty well on multiple platforms, and while the 2nd generation is still rather new it's the one currntly in the Grand Cherokee and also in the new Alfas and some other vehicles. The GC lists the 850RE, but uses the 8HP75 in their list, not 875RE, so dunno if it gets a new name, or if it gets it once it's made in N.Am. like the NAG1 (2012s JKs were W5A580s , 2013+ are NAG1s [though build sheet can still show W5A580] the have different programming and characteristics too).

Click on the transmission drop-down to see the 850RE & 8HP75;
http://www.jeep.com/model-compare/detailed-chart/?modelYearCode=CUJ201703

Now their 9-speed on the other hand, meh, it's had a ton of issues, including the early programming in the Cherokee, but some of that was rectified by an update, but it was still a little underwhelming. The 8-speed however has a pretty good reputation, and I'm happy to see it in the JL.

Some info on the 1st generation ZFs from the allpar site;
http://www.allpar.com/mopar/transmissions/ZF8.html

A graph of the lineup of 1st and 2nd generations variants with weight rating vs torque from ZF's site is attached.

 

[Indio]

Yeah, the ZF transmissions are pretty solid, and appear on a bunch of platforms from Jeep, Ram, BMW, Porsche, Bently, Range Rover, etc ...

Great info - thanks for all the details in your transmission posts.

 

[Superwinch]

Good to see we're getting a more efficient automatic But anyone have a guess why Jeep didn't go with the ZF 9HP nine speed automatic? It's already used in the Renegade and Cherokee and it'd probably be more efficient than the new 8 speed?

Size wise it's relatively small and light so it'd fit Wrangler. Max torque of 480 Nm / 354 lb-ft so it could be used with the Pentastar and Hurricane.

 

[The Great Grape Ape]

But anyone have a guess why Jeep didn't go with the ZF 9HP nine speed automatic?
...
Size wise it's relatively small and light so it'd fit Wrangler. Max torque of 480 Nm / 354 lb-ft so it could be used with the Pentastar and Hurricane.

A few things actually: first and foremost, it's a transaxle implementation, which doesn't work with many aspects of the Wranglers (real transfer case, solid axles, lifts) better for AWD + IFS vehicles; second because of it limited torque options it does mean you'd have two greatly different transmission ratios/spreads depending on platform, whereas the 8-speed offers same spread and ratios in two variants just different torque ratings; third and not minor by any means the ZF 9-speed has been a dog (no pun intended) for Jeep, Acura and LR, with tons of issues and now a sullied name, you don't want that question mark in a rugged off-roader's next gen update.

The ratios and spread of the 2nd gen 8-speed are good, while not as wide a spread as the 9-speed's 9.8x the 8-speed's 7.8x is still a significant boost over the existing options, and real world the difference becomes as X approaches zero.
Also importantly, the 8-speed's spread is actually better than that of Ford & GM's 10-speed (7.44x), so can be configured to offer both lower end and top end superiority over the competition with the right axle ratios.

Additionally the 8-speed's higher first gear ratio will give it greater PR crawl ratio numbers than anything out there with a Rubicon with 4.10 axle achieving an 82:1 ratio with the 8-speed, vs the 9-speed's 77:1 and the current NSG manual's 73:1 and current NAG auto's 59:1

Having driven the 9-speed in our Cherokee, I can tell you it's been annoyingly sluggish, jerky & noisey especially in the cold, and is usually in 7th or 8th thanks to engine management trying to keep it at optimal RPM and doesn't see any benefit to forcing it into 9th via the autostick, because it needs a certain RPM to generate enough HP for the engine to overcome resistance, so a lower ratio doesn't allow it to go down 100+ RPM.

Remember, regardless of the number of gears, you hit a wall where you can't go lower on engine output as you still require xxx HP in order to keep moving @ yy MPH, and all the ratios in the world doesn't change that, especially when driving a brick through the wind.

Which is why I think regardless of what they do engine wise, weight & aerodynamics will conspire to to reduce the overall impact compared to other vehicles and people expecting the big highway MPG hyper-mileing numbers will likely be dissapointed.

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