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  #25  
Old 09-21-2010, 07:10 AM
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Re: 8-Speed Box Before Long?

http://www.allpar.com/news/index.php...ore-on-the-way

8 speed for rwd applications, 9 speed for fwd applications. Introduced in mid-2011.
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  #26  
Old 09-21-2010, 08:42 AM
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Re: 8-Speed Box Before Long?

With 8 speeds, and now the announcement of 9 speeds, are we getting to the point of a CVT with just some interrupting "shift points" to pretend it's stepping and not stepless? I guess this is all about a means of supplying better fuel economy, but aren't we getting way over-engineered for this component?
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Old 09-21-2010, 08:44 AM
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Re: 8-Speed Box Before Long?

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Originally Posted by routh View Post
Bah you're killing me! I'm on the verge of buying now but if the 8 speed will be out for the 2012 model I could wait. I agree that they wouldn't go though all the work of putting in a new transmission for the SRT8 models only it will be on all or none. What would the cost increase be for the 8speed?
Why should there be price increase? AFAIK base Laredo 2011 sticker is actually less then 2010.
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  #28  
Old 09-21-2010, 09:20 AM
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Re: 8-Speed Box Before Long?

I wanna see a 8-Speed box drop soon, then i will place my order for an overland. Im kinda secretly hoping the mentioned summit edition overland will come out with the 8-Speed box, then i'm all over it!
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  #29  
Old 09-21-2010, 12:06 PM
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Re: 8-Speed Box Before Long?

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Originally Posted by Sparro View Post
I wanna see a 8-Speed box drop soon, then i will place my order for an overland. Im kinda secretly hoping the mentioned summit edition overland will come out with the 8-Speed box, then i'm all over it!
Good things comes to those who Waite.
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  #30  
Old 09-25-2010, 09:46 AM
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Re: 8-Speed Box Before Long?

Honestly, all this does not matter and is very difficult to discuss if they don't hint at the actual ratios of the gearing.

If they are able to offer down to a .50 overdrive or lower they would be able to step up to improved gearing in the rears like say 4.56's or 4.88's... this would make the vehicle more efficient down low and as it gets up to speed the combination would prove to be efficient in the top end as well... "Leverage is a bitch"! And using it to our advantage would make our vehicles much more fun to drive and fuel efficient.

Even with the current .75/.67 overdrive we have now, 4.56's would prove to be more fuel efficient due to the mechanical advantage they offer... which is backed up by simple math. But a numerically lower overdrive teamed up with such gearing would only offer greater gains do to the lower load on the engine at any given RPM.

And then their is the fact that the "LOAD" or "STRESS" is transferred FROM your engine/transmission and moved to the rear axle where it should be... So being able to run the numerical higher gear has many benefits...

I wish they would publish the numbers so we can play with the math variables.

I also wonder if this is just PROGRAMING of the 545RFE or if they are going to an entirely new transmission.... I think its still the same mechanically... just programing. They did the same thing with the 45RFE back in 2002... in 2003 they came out with the 545RFE which is the same exact transmission in every single way... The only difference between the two is programing. They just programed an additional overdrive into the software and boom your 45RFE is now a 545RFE.

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  #31  
Old 09-25-2010, 10:48 AM
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Re: 8-Speed Box Before Long?

This may be reposted old news but looks like the trans is already in use.
http://www.autoweek.com/article/2010...NEWS/100609858

http://www.bmwusa.com/Standard/Conte.../4mq6W1vORvg==


The company did not say which vehicles the transmission would be used in, but it is already being used in rear-drive vehicles made by BMW. Chrysler could use it in the Chrysler 300, Dodge Charger and Jeep Grand Cherokee along with Ram pickups.

Indiana Transmission Plant 1 currently makes the 45 RFE rear-drive transmission for the Jeep Grand Cherokee, Liberty, Dodge Dakota and Ram Trucks and the 68 RFE for the Cummins Diesel engine used in Ram Heavy Duty trucks.

The ZF eight-speed transmission made its debut on the BMW 5-series Gran Turismo and 760Li. The transmission achieves a 6 percent improvement in fuel economy over ZF's current six-speed automatic. It is the same size and lower weight than the six-speed.



Read more: http://www.autoweek.com/article/2010...#ixzz10Ya7wv5v
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  #32  
Old 09-25-2010, 11:55 AM
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Re: 8-Speed Box Before Long?

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Originally Posted by AIR_RAM View Post
...in 2003 they came out with the 545RFE which is the same exact transmission in every single way....
As I recall, my 45 became a 545 in 2000, but yes, it was just a flash to add the second overdrive. My WJ has 3.73 ratios, and I've considered those to be sufficient, although I'm not running large off-road tires. Yes, gearing changes are available for those axles, but have never been offered by Jeep, just the aftermarket. Your premise of a lower range may be acceptable with the new 8 speed, but I think they may just do this in the trans ratios rather than in the axles.
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  #33  
Old 09-25-2010, 02:07 PM
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Re: 8-Speed Box Before Long?

theres no aftermarket gears made for the current WK axles....so i doubt there will be anything soon for the 2011
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  #34  
Old 09-26-2010, 04:16 AM
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Re: 8-Speed Box Before Long?

The auto industry is just catching up to the mountain bike industry, that's all My first bike was a ten speed. Later, my first mountain bike had 18 gears. Later on, 21. A few years ago, 24 was the norm. Now they're at 27, and 30 is coming soon. I wonder if they'll add a fourth crank gear to bump it up to 40

There is more involved in fuel economy increases than the final drive ratio. Some cars get better mileage at 75 mph than at 60 mph, for example, even in the same gear. This is because the motor's maximum efficiency is reached at a particular RPM range, along with a drag coefficient which is low enough that the 15 mph increase isn't defeating the engine's efficiency gains. (That doesn't necessarily mean that only sleek cars meet this description though) It's not generally "lower RPM = more efficient".

For highway mileage, it's all about the final gear matching up the current travel speed with the engine's efficient RPM range. A lower OD gear isn't always better, if they already have the ideal OD gear. Having more gears in the tranny can help ensure the final gear is the ideally efficient gear for typical highway speeds, rather than a compromised range, as well as keeping the engine nearer to it's most efficient RPM range while in the varying speeds of city driving.

So, how much mileage increase can be had from a new tranny largely depends on how poorly matched the current tranny's gears are to the engine's max efficiency range.
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  #35  
Old 09-26-2010, 04:57 AM
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Re: 8-Speed Box Before Long?

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Originally Posted by HEMInator View Post
[URL] ...I would HAVE to think it will be available in the regular versions of the 2012 JGC as well...
Yes, absolutely 100%.
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  #36  
Old 09-26-2010, 09:23 AM
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Re: 8-Speed Box Before Long?

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Yes, absolutely 100%.
So are you saying their won't be any 2011 surprise 8-speed mid production units and we will have to wait until MY2012 for the 8-speed gear box?
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