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Old 07-18-2014, 04:05 PM
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After Tranny Flash 21-018-14

On Monday I had the 21-018-14 Tranny Shift and Diagnostic Flash and a Software Flash for PCM done.

Now I'm noticing a rev and surge when the car downshifts from 5 to 4 and to a lesser degree from 4 to 3.

And..... I've also noticed an "engine knock" sound during some acceleration scenarios. Can't say for sure if it is engine knock or not.

Has anyone else who's had these flashes done noticed the same phenomena?

2.4l 4x4 Latitude.

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Steve
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Old 07-19-2014, 08:26 PM
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Re: After Tranny Flash 21-018-14

That's what ours was doing before and after the 21-018-14 flash. The mountain pass we drive over frequently is fast road on our side and slow/twisty on the other. When we hit the top of the mountain we naturally lift off the accelerator. The KL, however, would do a 5-4 downsfift and rev up. This isn't just an annoyance, it's a definite safety issue.
I think the 4-5 and 5-4 shifts are the issue as this is the point in the shift pattern where the first dog clutch (F) either disengages (4-5) or engages (5-4). Dog clutches require a torque reduction and RPM match to take place to properly engage or disengage and the TCM programming seems to be at fault because of the lack of control exhibited during these particular gear changes. I only hope that Chrysler gets these things working as they should in the near future.
We just had the trans and TCM replaced after it decided to cook itself. The tranny seems to be doing OK, only time will tell I guess. We still notice funkiness in the 4/5 shifts and that has got to be totally a transmission control problem.
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Old 08-01-2014, 03:06 PM
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Re: After Tranny Flash 21-018-14

Quote:
Originally Posted by Fumbler View Post
That's what ours was doing before and after the 21-018-14 flash. The mountain pass we drive over frequently is fast road on our side and slow/twisty on the other. When we hit the top of the mountain we naturally lift off the accelerator. The KL, however, would do a 5-4 downsfift and rev up. This isn't just an annoyance, it's a definite safety issue.
I think the 4-5 and 5-4 shifts are the issue as this is the point in the shift pattern where the first dog clutch (F) either disengages (4-5) or engages (5-4). Dog clutches require a torque reduction and RPM match to take place to properly engage or disengage and the TCM programming seems to be at fault because of the lack of control exhibited during these particular gear changes. I only hope that Chrysler gets these things working as they should in the near future.
We just had the trans and TCM replaced after it decided to cook itself. The tranny seems to be doing OK, only time will tell I guess. We still notice funkiness in the 4/5 shifts and that has got to be totally a transmission control problem.
I have the same problem. I had hard upshifts at 1,2,3. I had the update applied and went on vacation. Going up hill in the smokey mountains it struggled to find the correct gear. On the down side of the range was heavy engine braking followed by a high rev down shift that made the vehicle accelerate.

Once we got to our destination i heard an engine knock when stationary in drive. It went away in park.

Lemon law time.
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Old 08-01-2014, 09:07 PM
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Re: After Tranny Flash 21-018-14

My wife had one instance of uncontrolled acceleration on her drive home from work where she entered a speed zone, lifted off the accelerator, and the car took off on it's own. She had to keep on the brakes until it decided to calm down. This speed zone is a 35, so that would put the car at a 5/4 shift. Chrysler Care said to take the car to the dealership (50 mi) so that they could assess the problem. The issue is we haven't been able to duplicate since that one instance. We've got about 1K on it since the tranny/TCM replacement, so I think maybe the kinks are worked out. I still don't like the downhill reaction of this 9-speed. It still feels like it's accelerating when your off the throttle and there's absolutely no compression braking unless you gear down a ridiculous number of steps, revving the engine way up.
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Old 08-02-2014, 08:06 AM
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Re: After Tranny Flash 21-018-14

Well, I brought the car back to the dealer for a re-check. After a test drive by a service manager, the diagnosis was that there "wasn't an acceleration problem". I was just "experiencing the sensation of the clutch releasing". That this was normal on the 5 to 4 downshift. "Before the TSB flash, this clutch release happened at the 6 to 5 downshift." (I never noticed this "sensation" then).

They said to keep an eye on the issue and if it got worse to come back in. They also said that the transmission tweeks were a work-in-progress and that there would very likely be another flash sometime down the road.
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