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Discussion Starter · #1 ·
Here are some figures I've comes across for ZF Equipped Jeep Renegades:

a 9.84 ratio spread (from bottom to top). First gear has been listed at 4.71 and then steps up incrementally. I believe 9th or the final OD is listed at 0.48:1...

Trailhawk does it one better i suppose. We know about the 20:1 crawl ratio, but I've also just come across its final drive of 4.334:1. Non TH AWD models equipped with the ZF 9 speed will also use the same 4.334:1 axle ratio with the 1.4 and 2.0 engines.

ZF equipped FWD and non TH AWD's using the 2.4 Tigershark will use a 3.734:1 ratio.

Of note is the Range Select setting so you can actually limit how many gears your 9 speed will use. Equally interesting is that the Renegades software system is able to choose from 20+ shift maps based on context. Selection inputs include engine characteristics, acceleration (forward or not), grade, speed, SC and temperature..

It really is quite the complex little unit...
 

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the ZF 9 speed is a wonderful transmission

When they get everything to work

I've read of some Cherokee owners having problems with their transmissions.
 

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I'm on a jeep forum, there seems to be a fix now with the latest firmware update. The update has only been out a couple/few weeks now so we'll see if it is 100% fixed.

Scott
 

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"It really is quite the complex little unit..."

Unfortunately thats a problem, they get to complex and it takes a rocket scientist to figure it out! When they're working correctly ther're great. Hope they get the bugs worked out before they start building the Renegade.
 

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I read that the tigershark engine is sluggish and the 9 speed transmission is choppy and unrefined.

This is concerning as that is the set up in the Trail Hawk Renegade.
 

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My concern with the 9spd is that with the Tigershark engine, it will never see 9th gear and rarely 8th because of the tall gearing and high torque peak of the Tigershark. The new Cherokee even with the V6 almost never sees 9th. So then, what is the point of all the gears, other than complexity, bragging rights, and cruising at 90 downhill at low revs?
 

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Discussion Starter · #7 ·
My concern with the 9spd is that with the Tigershark engine, it will never see 9th gear and rarely 8th because of the tall gearing and high torque peak of the Tigershark. The new Cherokee even with the V6 almost never sees 9th. So then, what is the point of all the gears, other than complexity, bragging rights, and cruising at 90 downhill at low revs?
well 8th and 9th are OD's anyways, so it behaves more like a 7 speed...
 

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My concern with the 9spd is that with the Tigershark engine, it will never see 9th gear and rarely 8th because of the tall gearing and high torque peak of the Tigershark. The new Cherokee even with the V6 almost never sees 9th. So then, what is the point of all the gears, other than complexity, bragging rights, and cruising at 90 downhill at low revs?
id imagine this can be changed with some programming
 

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Once you get to the 8 or 9 gear stage, I feel it is better to just move to a CVT at that point. I know the first CVT were kinda loud but, newer ones are a lot quieter. I believe we are getting to the point with auto trans that automakers will not be able to use them. Every time you add a gear, you increase the weight, cost, complexity and add another point of fail and each gear gets less efficient...a CVT perfected could resolve those issues.

Scott
 

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My concern with the 9spd is that with the Tigershark engine, it will never see 9th gear and rarely 8th because of the tall gearing and high torque peak of the Tigershark. The new Cherokee even with the V6 almost never sees 9th. So then, what is the point of all the gears, other than complexity, bragging rights, and cruising at 90 downhill at low revs?

@Newagejeep you can always head out to the desert and do top speed runs to get into 9th gear ;)
 

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Once you get to the 8 or 9 gear stage, I feel it is better to just move to a CVT at that point. I know the first CVT were kinda loud but, newer ones are a lot quieter. I believe we are getting to the point with auto trans that automakers will not be able to use them. Every time you add a gear, you increase the weight, cost, complexity and add another point of fail and each gear gets less efficient...a CVT perfected could resolve those issues.

Scott
As I understand it, while cvt can have lots of virtual gears, the maximum differential between the top ratio and bottom ratio is limited by packaging and there's other issues associated with creating enough friction to cope with power input while still being able to move it up and down the adjustable pulleys vs. packaging as well.

I don't think there is a free lunch to be had with either approach.
 

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i think there was an issue with chain driven CVT's or something like that, don't take my word for it though.
 

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Technology

I believe technology for multi-gear Automatic transmissions have only been waiting for production prices to fall.
 
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