I have a theory, based on this document:
https://docplayer.net/45447397-Tran...5447397-Transmission-control-module-tcm-adaptation-8hp45-845re-8hp70-8hp90.html

Issue is clutch B, and how it is fast fill adapting (or not) on the fly. A 5-4 downshift involves clutch B and D i think. Conditions under which clutch B will fast fill adapt is coasting with throttle at 0 position between gears 6-5. That often precedes a 5-4 downshift.

When i think back to when this occurs and how my driving style is (early coasting to reduce brake usage and a lot of around town driving never going much above 6th gear) i think the above conditions are occurring relatively often, and clutch B is either adapting improperly or not adapting/filling correctly or the clutch is worn. To be honest i'm not sure what that means but it would make since as it almost feels like the 5-4 downshift surge could be caused by a stuck or damaged B clutch. It would also explain the light slipping i thought i felt when accelerating in the lower gears that clutch B operates (1-5 and R)

If they perform a quick learn procedure to resit the adaptive, it should resolve the issue. My guess is the issue comes back pretty soon because we either have permanent clutch B damage or clutch B is not learning to act properly under our driving conditions.

Or it could be clutch C I guess - just throwing things on the wall and seeing if someone more knowledgeable can figure this out.

 

Update (not much of one)

Durango has been at the dealership going on 5 days. Day 2 they were supposed to replace fluid and valve body. Day 3 i called requesting an update. Was told they are waiting on approval to install the valve body. FCA wanted pictures and had to approve of the valve body install for some reason (they have one ready to go in). Day 4 nothing. Its now day 5.

This tells me either the issue is with the valve body or FCA is waiting to decide on a new valve body vs new transmission. Either way i'm not expecting to get it back soon. Dealership said the fluid looked good.

Now I'm curious if Durango's have a different valve body part number than Rams, to explain why similar complaints haven't occurred with Ram trucks. Or if there has been a part revision on vavle body's like there was with the water pumps.

Anyway, if others have 5-4 downshift lunges, it looks like it cannot be fixed with a reflash or a new transmission control module or an adaptive reset. It takes either new fluid and a valve body or a new transmission. I'll know soon enough

Here is a nice document, for your reading pleasure
http://perception.fcaperformanceinstitute.com/FCARepository_con/topiccontent/1588106484/0221308.pdf

 

Seems like the valve body may be the culprit.

Here is a website has has a bunch of valve kits to resolve shifting issues
https://www.sonnax.com/parts?&categories[]=3&makes[]=20&unit_relationships[]=439&unit_relationships[]=435&unit_relationships[]=9&areas[]=4

 

Update:
After 15 days at the dealership, got the durango back yesterday.

Replaced valve body (R8227332AB) and fluid (68218925AA), programmed TCM, and "performed drive learn"

They also performed the U06 recall which updated the TCM from 68249348AF to 68249348AG.

All covered under powertrain warranty vehicle has just over 43k miles

The valve body used to have a different part number ...AA, so the revision may have been made to correct this issue, or not. Looks to be the same one used for ram, charger, grand cherokee, and durango.

 

Glad to hear you have your ride back finally! Hopefully that solves the issue. When they replaced my valve body back in December 2018, PN: 68227332AD was used. I think this is new versus rebuild? (Just going off information online). But that may be a mute point since they replaced the whole transmission in January 2019.

Good luck!

 

Well that's a little concerning. The service department did say they had one already... which means they had a remanufactured one R8227332AB setting on the shelf and chose not to order a new one 68227332AD.....

Or now i'm wondering if the reason had to wait so long was because they sent my original valve body/core out to get refurbished....

Their excuse was that they have a valve body setting and waiting to go in but couldn't until they got official approval through STAR or chrysler...said they asked them for pictures, etc.

I assume official verbiage in the powertrain warranty allows them to do this, as opposed to replacing with a new part.

 

Improvement or placebo effect or ????

Since it seems that the whole issue has to be programming and how the transmission is learning and adapting over time, I decided to try an experiment. I've been saying for a while that when I paddle shift, the shifts are smooth. IowaRT's posts and linked transmission docs got me to thinking about ways to get the transmission to learn some smoother shifting habits.

As an experiment, I drove for a couple days where anytime I was decelerating to a stop (say, from 40mph or higher) I'd just tap the paddle once and let the transmission downshift the rest of the way on its own (which it does as your speed drops). Perfectly smooth, as expected. The downshift points are a little lower than if I was in "D" but no big deal.

The interesting thing I noticed is that when I'm driving in "D" now, the downshifts seem significantly improved. There are still some that are just as rough as before, but there seem to be plenty where I would expect it to be rough but it's not bad enough to complain about. Time will tell how this pans out, whether it learns its rough shifting again.

Or I could just experiencing the placebo effect. Or I could have adjusted my driving habits to minimize the conditions that result in rough shifting.

I'll let you know.

 

As an experiment, I drove for a couple days where anytime I was decelerating to a stop (say, from 40mph or higher) I'd just tap the paddle once and let the transmission downshift the rest of the way on its own (which it does as your speed drops). Perfectly smooth, as expected. The downshift points are a little lower than if I was in "D" but no big deal.

The interesting thing I noticed is that when I'm driving in "D" now, the downshifts seem significantly improved. There are still some that are just as rough as before, but there seem to be plenty where I would expect it to be rough but it's not bad enough to complain about. Time will tell how this pans out, whether it learns its rough shifting again.

Update: just over a week and shifting is back to being consistently rough. I'll probably try this again but I'm hoping that someone's experience with a dealship fix works long-term.

 

Reporting back - the new/refurbished valve body has completely resolved the downshift issue. Also have seen an improvement to MPG.

 

Hopefully everything stays good on yours. Mine was good for about 2 weeks after the transmission was replaced, then suddenly one day it was shifting hard again.

Edit: that was about 100 miles.

 

I know most of this seems to be R/T related, but I have had similar issues with my 18' SXT. I dont drive alot, and at 700 ish miles I started having an issue where it would basically "surge" when going down the road in 8th gear. Between 40-65 if I was just maintaining speed it would act like it was trying to shift, but wouldnt. RPMs didnt change. So I took it in, of course they couldnt recreate it and so they said they flashed it and it should be good. It still did it, but I started driving it more and more (longer trips), figuring it might be a learning thing. The surging stopped, but now the downshifts have started. Mine is the downshift to 5th gear. It is just as everyone else describes with the surge. Also, when I start mine up when its parked, it clunks.. like as if I put it in gear. But it is still in park.
I complained to the dealer about that and they said they could replicate it.

Our other vehicle is a 16 GC, and it has never had any issues like this with the shifting. It has low miles as well, 13K. Just kind of frustrating because it seems very apparent to me.

 

The 2018 V6 Durango uses a slightly different version of the 8-speed transmission (8HP45/845RE for the V6 vs. 8HP70 for the V8). Which engine is in your GC?
The variant for the V8 is beefed up a bit, not sure how similar the programming is between them. Given the differences in mechanicals, I would expect them to operate slightly differently.

 

Just out of curiosity, when it's downshifting, is it doing it kinda quick? Like on mine when coming to a stop, it is still in 4th gear at around 10 miles an hour or less. Now in Sport Mode it will downshift quick than that. I don't remember what gear I'm in at that speed, but it is lower than 4th.

I don't have the rough shifting issue on my R/T is why I ask this. My 5th to 4th is fine as well. Just wondered if maybe the transmission was downshifting faster than it is suppose to, possibly causing the rough downshifts. If that is the case, it would seem like the computer is telling the transmission to downshift too early. One would think the to PCM or what have you needs reprogrammed/replaced, maybe there is a bad batch of them? Especially after several of you have reported it came back after getting parts replaced.

Sent from my SM-G975U using Tapatalk

 

It's not really a matter of how quick/slow or when it downshifts as long as it's smooth. When I had the problem of 5>4 downshift, myself and others in the car, thought we got rear ended. It's that clunk/jolt when downshifting. Kinda like a bad shift when driving a manual where don't blip the throttle and release the clutch to quick.

Given that, programming could still be a root cause but after X miles of bad shifting due to programming issues, is there physical part damage as a result.

 

Gotcha, thanks for the clarification!


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I have a 2015 Citadel with the Hemi and about 40,500 miles now but around 38, 000 at the time.
I also had the very rough 5 to 4 downshift and occasional 2 to 1 rough downshift for the 3 years ive owned it. It seemed more pronounced with AC on initially but then was just rough all the time and like others have said it felt like i was rear ended and checked behind me a few times to see.
After reading here that not much can be done to fix it I never mentioned it to my dealer until I had a bigger problem with it. On 2 occasions the transmission clunked into 4th louder than usual and then resulted in a check engine light code P0734 and the vehicle in limp mode staying in 4th gear until i turned it off and restarted. First time I brought to dealer the light went off the morning i was bringing it in and they refused to do anything without an active code. Then after the 2nd time (about 3 months later) this happened i brought it right to dealer so the code was still active. At first they tried to just say it went out and is shifting normally now but I pushed them to look further to the cause of the limp mode and CEL. about an hour later they called and said they were going to replace the transmission and waiting on final approval from FCA. Then about a half hour after that they called back and said it was approved and on order. seemingly a total 180 as they were not going to do anything initially. I know it doesnt sound like it, but i really do like my dealer and service people. they have been very good overall, although sometimes quick to dismiss things at first but usually come through for me. Much better than any of the other dealers in my area have been.
about 3 weeks later i had the transmission replaced and since then Ive driven about 2500 miles and so far its been great. hopefully it stays this way.

on a side note: another issue i always had was on the first start of the day, the first 1 to 2 upshift was always delayed and kind of rough but that too has been rectified.

 

on a side note: another issue i always had was on the first start of the day, the first 1 to 2 upshift was always delayed and kind of rough but that too has been rectified.

I've had this happen, too. Not always, but often enough.
Good to know that it seems the problem *can* be resolved. :thumbsup:

Maybe it's going to take a second transmission replacement on mine.

 

Here's my latest update. Had the DD at the dealer for the last week after hearing that TSB 21-013-19 might be a fix. The TSB was issued 3/13/2019 so it's not too old.
Service order results show this:

Customer states transmission is not shifting correctly, also shifts very harsh, perform TSB 21-013-19 first and then advise

TCM not up to date. Need to reprogram module with latest software and test drive.

Updated TCM module to latest software per TSB 21-013-19 P#68249346AE/AF
LOP 18-19-05-LH .2 Test drove vehicle. Shifting became worse. Reset adaptives and performed quicklearn. Shifting was still harsh during 5-4 downshift. Performed ETC Learn and found Star Case S1421000017. Performed drive learn adaptation procedure TSB 21-030-14. Drove vehicle 20 miles. Set counters above 2 vehicle shifts are good. No further concerns found.

I just picked it up last night and only drove about 10 miles so far and it seems fine.k

Take-aways from this so far, IF it is a true fix:
1 - the service and tech were able to reproduce my problem. Service writer acknowledged that he's seen this quite a bit
2 - this is a software problem. Replacing hardware (TCM, PCM, valve body, entire transmission, etc.) might be required if anything got damaged due to extended periods of harsh shifting, but the FIX is software.
3 - unclear what specifically is in TSB 21-013-19 since I can't find it on the interwebs, but there is a TCM update since 12/26/18 when they indicated no TCM or PCM software available for me.
4 - there is a Star Case S1421000017 that relates to this issue
5 - after the TCM is updated, they need to do a drive learn adaptation, which was issued as a TSB back in 2014. This might not be standard procedure after doing a TCM flash.

I'll continue to give long term updates.

 

Here's my latest update. Had the DD at the dealer for the last week after hearing that TSB 21-013-19 might be a fix. The TSB was issued 3/13/2019 so it's not too old.
Service order results show this:


I just picked it up last night and only drove about 10 miles so far and it seems fine.k

Take-aways from this so far, IF it is a true fix:
1 - the service and tech were able to reproduce my problem. Service writer acknowledged that he's seen this quite a bit
2 - this is a software problem. Replacing hardware (TCM, PCM, valve body, entire transmission, etc.) might be required if anything got damaged due to extended periods of harsh shifting, but the FIX is software.
3 - unclear what specifically is in TSB 21-013-19 since I can't find it on the interwebs, but there is a TCM update since 12/26/18 when they indicated no TCM or PCM software available for me.
4 - there is a Star Case S1421000017 that relates to this issue
5 - after the TCM is updated, they need to do a drive learn adaptation, which was issued as a TSB back in 2014. This might not be standard procedure after doing a TCM flash.

I'll continue to give long term updates.

Following up on this - how has the Durango been driving? Any issues with shifting after a week?

Been going back and forth with my dealer and I’m hoping to use the info here to help them help me get the DD fixed.


Sent from my iPhone using Tapatalk

 

the website wk2jeeps that has the tsb's has finally been updated and there are a bunch of new ones there.
there is one pertaining to the trans and a TCM update from March. It addresses the 5th to 4th downshift problem. http://wk2jeeps.com/tsb/tsb_wk2_2101319.pdf

http://wk2jeeps.com/tsb/tsb_wk2_2101319.pdf

 

the website wk2jeeps that has the tsb's has finally been updated and there are a bunch of new ones there.
there is one pertaining to the trans and a TCM update from March. It addresses the 5th to 4th downshift problem. http://wk2jeeps.com/tsb/tsb_wk2_2101319.pdf

http://wk2jeeps.com/tsb/tsb_wk2_2101319.pdf

sorry just realized that this was already posted here but at least you can click the link and view it now.

 

Noticed yesterday when coming to a stop, the truck (2017 RT) would downshift hard and surge forward a bit. Watched the gear selection, and each time it was when going from 5th to 4th. Upshifts and the rest of the downshifts are smooth. This is NOT Sport mode, just normal, and no paddles. Seems like it waits an extra second, then hits 4th harder and lurches forward. Shut truck off in traffic and restarted. Next slow down was normal, then each time afterward it was back to hitting hard.

After work today, noticed same thing again. When I got home, I disconnected the battery and went for another ride. All was smooth again. But, then I noticed I was getting hot, so the AC was not on because I had disconnected the battery. Decided to turn the AC on and go for another ride. Yep, the hard downshift to 4th and surge was back right away.
It was warm starting yesterday, so in the last 1800 miles since new, barely had AC on other than defrost etc. Have no idea if AC has any connection.

Anybody had any hard downshift issues from 5th to 4th??? Feels like the ECM/TCM is getting screwed up or indecisive.

 

Hi,

I have the same issue with Durango R/T 2016 model. Brought it to the dealership for the 2nd time. Software upgrade didn’t help resolve the issue.

 

Sanjay, while it is possible you have a different problem than many of us have had, here's a quick test to see if it's likely the same or different. Instead of decelerating/cruising in "D" use the paddle shifters to downshift at the same speed that it would normally do it on its own. For me, that was downshifting from 5th to 4th at 25mph. If it's really smooth when you do that but not when it does it in "D" it sounds like you do have the same problem and it should be solved with the TCM update posted earlier.

It's important to make sure the dealer does a drive learn adaptation after doing the software update. The update itself seems to not do it. Print out and give them the TSB that describes the problem (even though it says it's for 2015 models).

 

I traded over the weekend a 14 for an 18 r/t. I noticed the hard shift on the 18 also. I thought I was just imagining it but I guess not!!

 

My 2020 RT, just started doing the 2-1 lurch forward when slowing down last week after not having done it at all for the first 1,000 miles of driving. I guess its back to the dealership for them to take care the issue. Any fixes available from the forum, it is annoying as hell when slowing down does it in all modes even manual paddle shift mode if you don't downshift when coming to a stop.

 

Any updates YouMadBro? My '20 R/T has always lurched on the 2-1 downshift from the beginning. Oil change and winter tire swap scheduled for Saturday at dealer and if it's simply a software update it sure would be nice. Thanks.

 

Let me know if you have any luck at the dealer, I wasn't too pushy with mine they have mostly been useless.

 

I will update. My dealer runs hot and cold with issues such as this.....

 

Would an aftermarket ECU correct this potentially? Does the Diablo unit for instance have any input into the transmission?

 

Sorry ahead of time for the long post. Hopefully you understand what I mean.

Anyway I have isolated the issue on my 2020 RT.

Issue: when coming to a slow stop the truck will sometimes surge / jump forward before coming to a complete stop. Almost like someone lightly rear ended you as you come to the stop.

Through some testing I can recreate the issue. In my truck if I find a downward grade and manually paddle shift to 3nd, then decelerate to 20 mph. Then very lightly brake to 16 to 17ish mph. The truck feels like it slips out of gear or goes into neutral and since you are on a downgrade the truck jumps forward. What's weird is that it is not shifting because after the jump the truck will be in the same gear it was before.

If you press the brakes hard enough you don't notice it, or if the grade is not steep enough.

It's not only with the brake depressed if you slow down naturally on the downgrade (like turning) it also can happen.

It can even happen when the truck is in manual mode via paddle shifters.

At first I though my 2nd/3rd gear was slipping but if you don't hit that speed it never happens it will engine brake forever going down the hill. Also if I rip it hard in manual mode in those gears it never does it. So I personally think it is a software based issue.

If you want to decrease it happening, on a downward grade shift back and forth between the gears giving you problems quickly, also while engine braking only (no brake pedal or accelerator). For me this stopped it from happening during normal driving but I can still recreate it manually with the paddles.

It seems like the tranny is programmed to prepare for a downshift when you are off the accelerator, in certain gears, and hit certain speeds, to make the downshift smoother. If you don't decrease speed enough it goes back into the same gear it was in before the bump, instead of keeping it in neutral or going down a gear.

Also it seems like eco/normal/sport all have independent learning as it happens in different modes until I do the above procedure.

 

I have a 2015 Durango R/T with ~60k miles. It started doing hard 5->4 shifts and occasional hard 2->1 shifts with the lurching forward. I did a bunch of research and found a post on another forum who suggested using AlphaOBD to reset the transmission.

I bought the AlphaOBD app for ~$50 followed the instructions and fixed it in about 15 minutes.

First, I reset the adaptive values, then I followed the quick learn procedure (see youtube link below for some instructions).

The transmission was immediately 80% better. Over the next 2 weeks it improved to the point that it is now perfect and functions as it did when brand new. It's now been about 2 months and I could not be happier that it was so easy to fix, especially after reading about all the hassle some of you have been through with the dealerships!
I can't promise it'll fix all your transmissions, but it certainly fixed mine.

In addition to the AlphaOBD app you'll need an OBD interface. I had a cheap Bluetooth elm327 module sitting around and it worked perfectly.

 

Thank you for your post!

I’ve been dealing with this for around five years, has the vehicle at the dealer when it started and they applied a software update which improved things temporarily but the problem recurred in a matter of weeks.

I bought an OBDLink MX+ and AlfaOBD and did the procedure yesterday.

My immediate impression is that it’s problem is solved though I’ll have to give it a few weeks, including an upcoming 1,000 mile road trip to be sure as the problem didn’t occur with every shift. Driving locally twice immediately after doing the procedure, the transmission downshifted smoothly, perhaps even better than when it wasn’t doing the extremely harsh 5-4 and 2-1 shifts.

I’d definitely recommend that anyone experiencing this issue give it a shot!

Lee Herman

I have a 2015 Durango R/T with ~60k miles. It started doing hard 5->4 shifts and occasional hard 2->1 shifts with the lurching forward. I did a bunch of research and found a post on another forum who suggested using AlphaOBD to reset the transmission.

I bought the AlphaOBD app for ~$50 followed the instructions and fixed it in about 15 minutes.

First, I reset the adaptive values, then I followed the quick learn procedure (see youtube link below for some instructions).

The transmission was immediately 80% better. Over the next 2 weeks it improved to the point that it is now perfect and functions as it did when brand new. It's now been about 2 months and I could not be happier that it was so easy to fix, especially after reading about all the hassle some of you have been through with the dealerships!
I can't promise it'll fix all your transmissions, but it certainly fixed mine.

In addition to the AlphaOBD app you'll need an OBD interface. I had a cheap Bluetooth elm327 module sitting around and it worked perfectly.

 

FWIW there have been several TSBs concerning shift quality over the years. Unfortunately chiltons website is not the most up to date (Alldata is better but you pay for a subscription) when it comes to TSBs but it is better than nothing.


2017

2018

2019

McDowell County Public Library - Chilton Auto Repair

mcdowellpubliclibrary.org

 

Thanks

 

I had same issue with my DD 2015 v8. Updating the TCM modules to the latest firmware an authorized Mopar fixed it for me