Hello All,

I purchased the vehicle of another member here, Norcalathlete in April. I'll give details in the post but the quick summary is I managed to fix the 5->4 and 2->1 downshift problems he was having. He was apparently on his 2nd transmission and still having this problem. I didn't notice at first when I test drove the vehicle but did notice it later. The 5->4 downshift would have a fairly harsh jolt and an audible "clunk" about 20% of the time. The 2->1 downshift would not make any noise but would have a bump sensation almost at the same time the vehicle would come to a complete stop, maybe 75% of the time. If I put the vehicle in sport mode, the 2->1 bump would go away and I also never noticed the 5->4 clunk but it is possible I just didn't use sport mode enough. After doing what I describe below, the transmission is now very smooth and I haven't felt any jolt or bump for about a month now. I did several things that I will describe below. The order in which I did things doesn't make it 100% about what exactly fixed it but I think after reading it, most people would agree on what the cause was.

1) I noticed that the speedometer wasn't adjusted for the bigger tires on the vehicle. When going 70mph (according to the speedo) the actual speed was ~74mph. I used AlfaOBD to correct the tire size and get the speed on point. This did not fix the transmission.

2) On about a 1hr drive on the highway, I noticed the transmission getting way too hot. With only me as the passenger and no payload the temperature was getting to about 230C on flat highway. I posted a thread with temperature plots describing the problem here: https://www.dodgedurango.net/threads...2/#post-804167

3) As described in the post link given above, I checked the transmission oil level following this link: I made one adjustment to this procedure. Since the transmission in the durango is not mounted level, I had to lift the backend about 1 foot. This has the effect of raising the fill port. Without doing this, the transmission fill level will be low. Surprisingly I found the transmission to be overfilled by about 1.5qt. After getting the level correct, the temperature of the transmission dropped down to ~195C and with aggressive driving, I could only get it up to 197C. This temperature plot is also in the forum link given in (2). The gas mileage also went up by at least 3mpg, probably closer to 4mpg. The rough shifting however was not fixed.

4) Okay, time to get into resetting and learning the adaptives. I didn't want to do this because the procedure is a major pain. After having done it, I am not surprised that people report problems, This procedure requires long flat roads with no traffic so you can do the procedure without interference. Where I live, that is a tough find. I imagine a lot of dealerships just skip it. It also takes several hours and you have to closely monitor the torque, rpm, and speed to trigger the learning events in the transmission.

5) I checked that adaptive values and counts using OBDLink MX+ and the included software. Two of the values are counts of learning events for the adaptives and two of the values are the adaptives (4 for each clutch makes 20 total). I noticed that two of the counts (one for clutch C and one for clutch E) were at the value 255. The significance of this number is that it is the maximum number that can be stored in 8-bit binary form. In other words, these two counts were maxed out. I am guessing that this means the transmission stopped learning for these two clutches. Also of note is that these two clutches are responsible for the 5->4 and 2->1 downshifts.

6) I first tried resetting the adaptives using the Tazer. It did not work for me. At least it didn't reset the counts... I didn't check the adaptive values so maybe it was only resetting those.

7) Next I tried resetting the adaptives using AlfaOBD. This worked and all 20 values were reset to 0.

8) I followed the procedure here to "learn" the adaptives: https://docplayer.net/45447397-Trans...p70-8hp90.html . There are two parts, 1) Fast filling adaptation and 2) standard clutch filling adaptation. (1) will populate the clutch filling pressure adaptives and the associated "fast-filling" counter, (2) will populate the clutch filling time adaptives and the associated "filling" counter. For me, after I did both (1) and (2), the transmission magically became very smooth. The torque, rpm, and speed must be monitored closely and kept within the values given in the procedure or the transmission will not learn. This turns out to be very difficult. I used the OBDLink MX+ software to do the monitoring.

Summary: Transmission was overfilled by about 1.5qt probably causing the learning procedure to not work correctly and maybe leading to excessive learning events for clutch C and E thereby maxing out the counters. This also caused the transmission to run hot and the car to have poor gas mileage. After setting the fluid level correctly, resetting the adaptives, and doing both steps of the learning procedure the 5->4 clunk and 2->1 bump are both gone and the transmission runs very smooth.

It reflects pretty poorly on the Dodge dealership that the vehicle could get into this state after apparently being taken in multiple times for poor shifting. I have been trying to figure out how they could even overfill the transmission. Since the fill port is also the fluid level, it seems almost impossible to overfill. The only thing I can think is if they jack up the passenger side of the vehicle this would allow the transmission to be overfilled.

 

I joined just to post this, hopefully it helps someone smarter figure out the exact issue.

I just started having a similar issue and can reproduce it pretty well in my truck. The issue seems to be programming but may be mechanical (I'm not a transmission expert).

Anyway my truck is a 2020 RT AWD. When approaching a stop sign/light sometimes the truck will jump / lurch forward right at the tail end of the stop. Like being rear ended lightly or tapping the gas.

From my testing there is more then 1 thing going on. At first I thought it was a shifting issue from 3rd to 2nd or 2nd to 1st, then a slipping 2nd gear, but now I think it's probably programming. Here's why I say that.

If I find a decline and paddle shift into 2nd and let it wind to say 3k rpms with no gas no breaks (engine break). As soon as I lightly press the break it seems like it tries to shift and jumps forward.

However the thing is the truck is not going into 1st or 3rd as if I let off the breaks after the jump starts it's still in 2nd.

I thought it's slipping out of gear perhaps, but if I do the same thing and never hit the breaks, it won't do it. You can gas it going down the same hill. And rip out in 2nd hard and no slipping so I don't think it's slipping out of second.

I think that it thinks when you are in second (which without paddles is usually pretty slow) and decelerating that when you hit the breaks it thinks it should prepare to shift as you probably want to stop fully.

The thing is you can't apply the breaks too hard or you will either be going to slow too feel it, or hold it back from doing it with the breaks.

As far getting rid of it, if I paddle shift into 2nd on flatish ground. Let it coast and immediately puddle it to 3rd then right back to second. It will sometimes do the same thing where it lurches forward. After doing that about 5 to 10 times, now in daily driving it seems like it is gone completely.

Not sure if any of this applies to other gears as I only get it in 3 > 2.

For my truck it seems to be related to brakes, so maybe as pads wear and you don't get the same stopping power, it isn't holding the truck on inclines as well.

I have about 35k miles on my truck and it started doing this in the last 5k to 10k miles.

 

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 above by "cu_alum" 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).

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.

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.

You Tube

 

Crossing my fingers that this works and lasts!