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Topic Review (Newest First)
01-02-2013 12:42 PM
MikeK46 I posted this in your other thread:

The OEM 18" tires are slightly taller than 32" and most "33's" are a few tenths under 33". The difference is almost non-existent, a few revolutions per mile.

The transmission determines when to shift based on many factors, including engine speed, throttle position, engine intake vacuum (a function of throttle position and engine load), road speed, and trans. temperature.

The unsprung weight of the tires will have a much greater impact than a few tenths of height. There will be more load on the motor, having to deal with the additional resistance of the extra weight. This means that at the same throttle position as before, intake vacuum will last longer and the motor will therefore rev higher before upshifting. Is this perhaps what you're referring to?

But like I mentioned, it's also adaptive and will learn your driving style over the first 50 warm up cycles. If you have a lead foot, yours will hold the revs longer than mine. If you're inconsistent (light foot some days, heavy foot other days) that's when you might find issue with it. They assume the same person driving the vehicle consistently.

Try resetting the ECU to clear the learning module and then drive it like you normally would to re-program it with your new tires.
01-02-2013 11:17 AM
scubatech M998,

Your right about this being a tuff tranny. Also these are computer contolled transmissions and are very sensitive to throttle inputs and gear & tire changes. One has to be very careful on these upgrades. These V6 engines are high performance but have to be revved to keep in the power band, Some of these jeep builds go from 4200 lbs / 2door to up near 5000 lbs. 4 door with bumpers tires etc. So it confuses the hell out of these things.
01-02-2013 10:21 AM
KittyPrawn
Quote:
Originally Posted by jadmt View Post
That is normal, that is how they are suppose to work. I can soft foot mine and get it to shift at very low rpms but I like it shifting at 2500-2600 in normal driving. I like it shifting higher when I romp on it and it does that. I might have gotten lucky but my tranny shift points seem well suited for my 3.21 gears.
Ah, didn't know it was supposed to work like that. Of course, everything being said... I don't think my JKU shifts poorly for the way that I drive.
01-02-2013 10:02 AM
jadmt
Quote:
Originally Posted by KittyPrawn View Post
Stock Rubicon with 4:10s and mine shifts about the same. Of course, I'm not easy on the gas pedal, especially going from 1st to 2nd. Usually I'm mashing the pedal to speed up quickly.

I don't know if it is coincidence, but my previous Pontiac reacted the same way. Sometimes it didn't want to shift until I lifted my foot off the gas pedal for a brief second. Again, could be coincidental or my imagination.
That is normal, that is how they are suppose to work. I can soft foot mine and get it to shift at very low rpms but I like it shifting at 2500-2600 in normal driving. I like it shifting higher when I romp on it and it does that. I might have gotten lucky but my tranny shift points seem well suited for my 3.21 gears.
01-02-2013 09:55 AM
KittyPrawn Stock Rubicon with 4:10s and mine shifts about the same. Of course, I'm not easy on the gas pedal, especially going from 1st to 2nd. Usually I'm mashing the pedal to speed up quickly.

I don't know if it is coincidence, but my previous Pontiac reacted the same way. Sometimes it didn't want to shift until I lifted my foot off the gas pedal for a brief second. Again, could be coincidental or my imagination.
01-02-2013 09:47 AM
jadmt I drive a charger at work and it shifts the same way to me. I am not sure if the tranny is the same in the two but they hold up to quantum amounts of abuse. I think it is the same tranny that the 5.7L ram uses. I am guessing the tranny is ok.
01-02-2013 02:15 AM
m998dna Yeah ... and if you want to add more to the beast call Paramount.

News « Paramount Performance Products

.
01-02-2013 02:00 AM
Braveheart12JK I haven't heard a lot on the longevity of this tranny, but I have heard that it's fairly bulletproof and it can handle plenty of HP and TQ. This would lead me to believe that it has good lasting power....that being said, it is one crazy beast. lol
01-02-2013 01:30 AM
m998dna
Quote:
Originally Posted by MikeK46 View Post
An auto trans outlasting the motor? That wouldn't say much about the Pentastar.
The trans is a proven application in the AMG Mercedes E55, Grand Cherokee SRT8, etc.... I think the Pentastar has a way to go to show its stuff.

Therefore at this point I'd place my bet on the trans.

.
01-02-2013 01:16 AM
MikeK46 An auto trans outlasting the motor? That wouldn't say much about the Pentastar.
01-02-2013 01:09 AM
m998dna
Quote:
Originally Posted by The_Chief View Post
I love my Jeep, but there's a lot of bullshit that goes along with it, more than any other car I've previously owned, including the cheaper ones...

I can't see such an inconsistent transmission lasting 100,000 miles ... How would that be possible when its mood changes by the minute? Lol

It will outlast that 3.6L its bolted to... it can withstand about 600 HP stock.

.
01-02-2013 12:47 AM
The_Chief I love my Jeep, but there's a lot of bullshit that goes along with it, more than any other car I've previously owned, including the cheaper ones...

I can't see such an inconsistent transmission lasting 100,000 miles ... How would that be possible when its mood changes by the minute? Lol
01-02-2013 12:30 AM
Braveheart12JK I agree with the OP. I have a '12 with 33" tires and 4:10 gears now, did the Procal adjust and the tranny still seems to have a mind of its own. Note: it seemed like that with the stock tires and 3:21's too though. Sometimes it shifts crisp and sporty, other times it seems to climb higher into the RPMs before shifting, even under easy acceleration. Hmmmmm
01-02-2013 12:00 AM
The_Chief Bump...want more opinions please.
01-01-2013 10:25 PM
American dream
Quote:
Originally Posted by The_Chief View Post
What's your rpm range (light-heavy accel.) for a 1st-2nd gear shift...? Please disclose if you're stock or running bigger tires, gears, etc... Thank you, guys!

I just think this tranny is unpredictable at times...
My 13 is stock and like you say the transmission never seems to sift the same way twice.
01-01-2013 10:13 PM
The_Chief
Quote:
Originally Posted by jadmt View Post

seems perfect to me. Mine does shift at at higher rpm as well when cold and first starting out. I think at 34" tall tires you would benifit from getting a procal to adjust the speedo/odo.
You're probably right about the procal... Why do you think these things shift at such a high rpm when cold? I thought I bumped the shifter into manual mode for a second, but it was in D.
01-01-2013 10:01 PM
jadmt
Quote:
Originally Posted by The_Chief View Post
I have 34's, 17" wheels, 3.73 gears... I didn't adjust the speedo... I get the same results as you--seems kinda high... I especially notice a high rpm shift into 2nd when the motor is cold...very strange...
seems perfect to me. Mine does shift at at higher rpm as well when cold and first starting out. I think at 34" tall tires you would benifit from getting a procal to adjust the speedo/odo.
01-01-2013 09:57 PM
The_Chief
Quote:
Originally Posted by jadmt View Post
mine is a 2013 with 3.21's and 265/75-16's and it is 1st/2nd consistently is 2500-2600 rpm under normal driving. If I really romp on it then it is much higher. I have a aev procal and have adjusted my speedo for tire size. under normal conditions it shifts just above the green on the tach.
I have 34's, 17" wheels, 3.73 gears... I didn't adjust the speedo... I get the same results as you--seems kinda high... I especially notice a high rpm shift into 2nd when the motor is cold...very strange...
01-01-2013 09:41 PM
jadmt mine is a 2013 with 3.21's and 265/75-16's and it is 1st/2nd consistently is 2500-2600 rpm under normal driving. If I really romp on it then it is much higher. I have a aev procal and have adjusted my speedo for tire size. under normal conditions it shifts just above the green on the tach.
01-01-2013 09:27 PM
The_Chief
2012-'13 auto trans. rpm shift points

What's your rpm range (light-heavy accel.) for a 1st-2nd gear shift...? Please disclose if you're stock or running bigger tires, gears, etc... Thank you, guys!

I just think this tranny is unpredictable at times...

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