Transmission not as crisp as I expected

rickinAZ

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I have less than 1,000 miles and I'm not as impressed with the 8-speed as I thought I would be. I'm sure that it's performing fine but I expected quicker and more decisive downshifts when I step on it. Not a big improvement over my JK's 5-speed auto in that one dimension. Besides the diesel, I expected the tranny to be the biggest improvement over the JK. Additionally, I think that FCA has a "safeguard" on the diesel engine/transmission to initially take some of the edge off the torque delivery - at least from a dead stop. I could be wrong, but there is a subtle hesitation that I don't attribute to turbo lag.





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Bruce Willys

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I have less than 1,000 miles and I'm not as impressed with the 8-speed as I thought I would be. I'm sure that it's performing fine but I expected quicker and more decisive downshifts when I step on it. Not a big improvement over my JK's 5-speed auto in that one dimension. Besides the diesel, I expected the tranny to be the biggest improvement over the JK. Additionally, I think that FCA has a "safeguard" on the diesel engine/transmission to initially take some of the edge off the torque delivery - at least from a dead stop. I could be wrong, but there is a subtle hesitation that I don't attribute to turbo lag.
I would bet it has more to do with tuning for emissions considering that the BMW X5 M uses the same transmission ZF 8HP75 while making 617 HP and 553 lb-ft (which according to Wiki is the maximum amount of torque that it's rated for). A tune would most likely go a long way to solve your woes once they're out.

https://en.wikipedia.org/wiki/ZF_8HP_transmission
 

oldcjguy

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With the eight speed it's more about the gear ratios and no "dead zones". The 5 speeds were notorious for the dead zone between 3rd and 4th gear. To much of a gear ratio spread. The 8 spd seems to always have a proper gear to be in for the situation. The trans can be made to shift very fast. But it's a jeep and not what it was tuned for. On a bouncy dirt road you don't want it so that it downshifts right away and bangs gears when your foot is being bounced on the fun pedal. I believe Diablo Sport released transmission tuning for the JLs. Tarns tuning makes a big difference in drivability and feel. These transmission controllers are very advanced and there's a lot that can be done with them just through tuning. Just ask Mustang guys. That 10 speed auto is horrible from the factory, but REALLY good after being tuned.
 

aldo98229

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The 3.6 V6 with the 8-speed automatic is a match made in heaven. The transmission is always on the right gear, responds immediately and decisively to the throttle, and holds the gear on descents by just a couple of gentle taps on the brake.

I’ve read that the EcoDiesel has a lagged response. Perhaps that’s what you are feeling...?
 

mgroeger

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I'm betting it's your diesel(or that safeguard you mention)...not the tranny. The trans in our 3.6L is super responsive. Best auto I've driven....and I've got a bit of experience with the PDK.
^THIS

Even with improper gearing in my wife's rear axle (still running 4.10s with 37" tires) I am dumbfounded at how responsive the tranny is. It will dump gears in the blink of an eye and take off like a rocket ship, that seems to be the general concensus as well. She's paired up to the 3.6L and I know the 2.0 turbo is a peppy little bugger. My guess is it's the diesel you are paired too.
 

Atticus

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The Diesel for sure does not have the responsiveness as the gas engines. This is my third Jeep. I have the 2018 JLUR 2.2L Diesel this time because I am now living in Germany. I was not that happy with the lag when pressing the pedal down. I recently bought the Pedalbox and it greatly improved the responsiveness.
 

DaltonGang

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Drive a Wrangler, with a 3.6 V6 in it, then get back to us, on how the tranny is. As someone has stated, it could just be soft tuned, for the diesel engine.
 

BrntWS6

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The Livernois transmission tune makes a world of difference from stock. I never really had any complaints with the OEM setup. But once I installed their tune and gave it some miles to adjust I could see how much it can be improved upon. It also made 8th gear more usable. My Jeep would always hunt for 8th, now it finds it consistantly.

Between the new steering box, Livernois trans and motor tune it feels like a whole new Jeep.

Unfortunately I don't think they have a tune for the turbos or the 3.6 with etorque.
 

Notorious

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Not getting what you are trying to say.
Inside joke with the member I referenced. We like to post sentences on topic that say one thing but mean another.

As for the topic, I think you’re right. The issue may be the diesel engine, not necessarily the auto transmission.
 

DaltonGang

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Inside joke with the member I referenced. We like to post sentences on topic that say one thing but mean another.

As for the topic, I think you’re right. The issue may be the diesel engine, not necessarily the auto transmission.
Oh, OK.
But, back on subject, the diesel trucks I have owned, and their trannys all shifted in a sluggish manner compared to their gasoline counterparts.
Personally I like a crisp shifting tranny, even in a diesel. But, that has only happened after a good rebuild of one. I need to test drive a New Diesel Truck, to see if the manufacturers are still doing this.
 

cosine

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I'm betting it's your diesel(or that safeguard you mention)...not the tranny. The trans in our 3.6L is super responsive. Best auto I've driven....and I've got a bit of experience with the PDK.
i second that. the 3.6 with the 8 is the best combo.
 

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