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  #85  
Old 03-12-2015, 06:20 PM
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Re: Clunk/thunk on 6-5 coasting downshift.

I have news as well...I got back from a trip today and picked up the Jeep (they also had to replace the steering wheel...another story). At this point I am only really using this Jeep as a testbed to determine whether the tranny issue CAN be fixed, as it has so many other issues I'm going to get it repurchased eventually anyway. However if the tranny issue is sorted I will get another Jeep SRT, despite all the problems I like them that much.

So, the FCA engineer looked at the car and determined that this was likely a characteristic of the vehicle at this time, and believes the upcoming software update (~1 month) should address the jerking issue. In the meantime he and I discussed that he should leave the battery unhooked and let the TCM completely reset to restart the "learning" process. This was done prior to me picking up the car.

When I started driving the car it had already been warmed up pretty well (it was also warm here, in the 80's), tranny was ~160F. On the way home, I had several opportunities to coast/brake gently to a stop. I can report there was NO, ZERO jerk from 6-5 or in any other gear, literally it was impossible to tell it had downshifted without looking at the indicator in the cluster. This was the case at least 4 or 5 times on the way home. However, by the time I got home I noticed it had started to get a little rough on the 6-5 shift (tranny was ~200F at this point), but I still hadn't started hearing the clunk yet.

This leads me to believe the transmission IS mechanically capable of a very smooth shift, and lends credence to the idea that a software update could resolve the issue.

In short, there's hope boys...I'm ready to stay the course and at least remain open to ordering another one of these if they can get the software right.. Without this critical issue, it's a great vehicle, even with the other problems I've experienced which I believe mostly to be flukes or relatively minor/fixable.

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  #86  
Old 03-12-2015, 06:41 PM
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Re: Clunk/thunk on 6-5 coasting downshift.

I'm telling you I have the solution right here. Just turn the switch to off when you put her to bed at night. Then in the morning rotate it back to on and off you go.

ImageUploadedByJeepGarage1426203673.895465.jpg


It even matches the brake calipers.


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Old 03-12-2015, 07:11 PM
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Re: Clunk/thunk on 6-5 coasting downshift.

Quote:
Originally Posted by rlarsen462 View Post
When I started driving the car it had already been warmed up pretty well (it was also warm here, in the 80's), tranny was ~160F. On the way home, I had several opportunities to coast/brake gently to a stop. I can report there was NO, ZERO jerk from 6-5 or in any other gear, literally it was impossible to tell it had downshifted without looking at the indicator in the cluster. This was the case at least 4 or 5 times on the way home. However, by the time I got home I noticed it had started to get a little rough on the 6-5 shift (tranny was ~200F at this point), but I still hadn't started hearing the clunk yet.
This leads me to believe the transmission IS mechanically capable of a very smooth shift, and lends credence to the idea that a software update could resolve the issue.
In short, there's hope boys...I'm ready to stay the course and at least remain open to ordering another one of these if they can get the software right.. Without this critical issue, it's a great vehicle, even with the other problems I've experienced which I believe mostly to be flukes or relatively minor/fixable.
That's awesome. Very awesome. I hope that does the trick.
I wonder if using a different grade transmission fluid work work? I have read that the fluid in the SRT's transmissions are very lightweight, if I recall correctly. (I am trying to find the webpage where I read this.) I wonder if that has a role in the transmission acting the way it acts when it gets cold? I would "assume" a thicker transmission fluid, (if usable), could help this clunk issue? Just a thought. Maybe someone with more mechanical experience can chime in on this.
Good luck!

**edit - found a website that states it uses a low viscosity transmission fluid.
http://www.allpar.com/mopar/transmissions/ZF8.html
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  #88  
Old 03-12-2015, 09:50 PM
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Re: Clunk/thunk on 6-5 coasting downshift.

I too can report that my transmission has been shifting much smoother since a battery disconnect. It has been about 400km since then and it does happen periodically, both the clunk, and the jerking downshift. I have been closely watching this thread to hear when this software update is out. Anxiously waiting.....
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Old 03-13-2015, 09:15 PM
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Re: Clunk/thunk on 6-5 coasting downshift.

No news to report on my SRT other than they have ordered two new headlights to replaced the originals due to water in them. Funny, my old dealership said Chrysler wouldn't replace these under warranty. My new dealership is replacing them without me even complaining. Also they spent some time trying to isolate where the clunk noise is coming from, but so far are unable. Hopefully more news next week.


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  #90  
Old 03-13-2015, 11:45 PM
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Re: Clunk/thunk on 6-5 coasting downshift.

At least your making some progress, new lights, one less thing to worry about, hope you have some luck with the trans and clunk also
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  #91  
Old 03-14-2015, 10:17 PM
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Re: Clunk/thunk on 6-5 coasting downshift.

brought mine in for the same problems and they tell me the transmission needed an upgrade how idk i love the jgc but is annoying with the rocky shifting in it
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Old 03-18-2015, 03:21 AM
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Re: Clunk/thunk on 6-5 coasting downshift.

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Originally Posted by bmackin View Post
I've got the same thing, but it's more like the 5-4 shift for me.

I'm taking it in to Jeep in a few week so they can have a closer look. The attitude so far hasn't been encouraging.

I've also got a rough idle on cold start and my U-Connect crashes if I plug my iPhone6 in via the USB cable. So far they've told me there's nothing they can do about any of them. I LOVE the car, but unfortunately Jeep service isn't always the best. It's an unfortunate tarnish on such a great vehicle.
Took mine in today for the 6-5 clunk with 1000km on it and all they did was "Reset TCM adaptive values and road tested"(Whatever that means)
Then advised me that "It will have poor shift quality until vehicle relearns its shift pattern"(Told at least 1000km) It was exactly the same as I'd dropped it in. Pretty disappointing. I'm assuming you have taken yours back to the same dealer I did.(any luck)?
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Old 03-18-2015, 09:18 AM
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Re: Clunk/thunk on 6-5 coasting downshift.

Yes it is frustrating to take a car in to have the transmission looked at and they tell you it's needs an update idk how that's possible mine usually has a delay when accelerating on the highway it's actually really scary sometimes.


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Old 03-18-2015, 03:12 PM
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Re: Clunk/thunk on 6-5 coasting downshift.

Mine's horrible now...just clunking and banging all the way down, big "play" feeling when getting back in the gas, then "bang" I start moving forward...it's like something is getting looser.

Starting to find it hard to believe a software update's going to fix this...but a tranny didn't either. There's something mechanically messed up.

There's some merit to the thing I read about using a very thin fluid too, since that would make sense given it gets so much worse when hot (fluid is even thinner when hot).

Whatever...just driving it now until I figure what else to buy so they can buy this POS back.
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Old 03-18-2015, 04:02 PM
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Re: Clunk/thunk on 6-5 coasting downshift.

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Originally Posted by rlarsen462 View Post
There's some merit to the thing I read about using a very thin fluid too, since that would make sense given it gets so much worse when hot (fluid is even thinner when hot).
Yes.
That is what I posted about a week ago. I wonder if a thicker fluid would help?
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Old 03-20-2015, 04:14 PM
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Re: Clunk/thunk on 6-5 coasting downshift.

Here is an update on my SRT

The service techs have traced the clunk noise down to a carrier bearing on the rear drive shaft using a stethoscope. According to the four techs that have been working on it this is the source of the problem. A new drive shaft has been order and should be in next week Tuesday. The service manager didn't seem 100% convinced that it was the problem, but that the direction they are heading. I'll update again when I hear more.


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