Hi All,

I’m leasing my fourth MDX but am new here! With my last MDX (2017), the car would go from D into S all on its own- I wouldn’t touch a thing! Long story short, I offloaded the car because I thought surely something was wrong with the transmission! Well, as luck would (or wouldn’t) have it, here I am with a brand new 2020 MDX and it’s doing the same thing. Either this is something that this car just does or I have the worst luck with these MDXs. Can anyone shed any light on this? Not even the dealership seems to have any insight. Again, the car is normal Dynamic mode, I’m not touching the gear selector, nor are my hands anywhere near the paddles. I’ll just be driving along and feel a shift and then I’ll look at the display and see that the car is now in S and no longer in D.

Thanks!

 

Could you upload a video of this happening? This sounds like more of a software issue in the TCM that Acura needs to address.

 

That's it's way of telling you you're not driving fast enough....

 

Very strange. Hope you get this worked out.

 

First tranny problem of this kind ever reported on the 3G MDX forum. Even more strange is that the exact same problem happens to 2 different 3G MDX's you own.

 

which leads me to think it is a driver issue, not a car issue. Im starting to think the OP is hitting the paddles by mistake.

 

It's definitely an electrical problem, and not a mechanical problem

 

Paddles don't switch the trans from D to S. It would change the gears regardless if its in D or S.

 

One interesting story about my wife who complained to me that our 2014 MDX (with stick transmission selector) would shift from D to N randomly when she applied the brake to stop the vehicle.

Later, I found out that my wife loved to put her handbag on the lid of the center console storage bin, right behind the transmission stick. So whenever she braked hard, the heavy handbag shifted forward, pushing the transmission stick forward as well, and resulting that the transmission mode went from D to N "by itself". This didn't happen all the times, because light braking would not cause the heavy handbag to shift position.

So mystery solved. It's human operation error.

 

Makes sense if you have a shifter. OP says they now have a 2020 and is experiencing the same auto shifting. We all know there are no longer shifters in these vehicles. We have buttons.

This is a head scratcher to me. I'll be watching to see what comes of this. Sort of suspicious it is happening to the same person in two different vehicles.

 

LOL, I get so OCD when I wife place her handbags near the shifter. Drives me absolutely insane having anything near those shift buttons.

 

They do. You can switch from D to S and vice versa with either the D/S button on the center console or by using the paddles.

 

The OP sees the display switching from D to S. The paddles can manually change gears all right, but they can't change the tranny mode as shown on the display indicator.

 

For 2016-2020:
If you pull on the paddles while in D mode, you can manually shift the vehicle temporarily. If you are on level ground at constant speed, the transmission resumes automatic shifting after 5-10 seconds of not using the paddles, and the gauge reverts to displaying D. This is useful for short-term acceleration and engine braking. Without using the D/S button on the gear selector, the transmission will not switch to automatic sport shifting logic (S).
If you pull on the paddles while in S mode, the transmission switches to manual shifting and will hold whichever gear you select until you reach redline or change the gear yourself.

Summary:
D with paddle pull = temporary manual control which reverts back to automatic
D with D/S button push = full automatic sport shifting logic, S displayed on MID
S with paddle pull = manual shifting (automatic upshift at redline)

 

on our hybrid using the paddles will still show "D" along with the gear selected e.g. "D2" The display won't say "S" unless I select S+ mode or hit the D/S button or mode button below it to shift to S.

 

Please make a video showing how this can happen using paddles and upload it. I cannot replicate it on my 17 MDX using the paddles to shift it to S; it does upshift and downshift in whatever mode I am in. Mode = D or S. And I personally keep my MDX in the Sport Dynamic Setting all the time.

 

This same thing happens to my 2020 MDX as well and here is what I have noticed: 1. This S mode is visually different from when I put S mode intentionally. It shows in normal drive mode color and not in reddish color. 2. If I put the car in park and then go back on D, it goes back to normal D mode 3. The only other way to get out of this S mode is to restart the car (cannot change it from the driving mode selection menu).

Was any resolution found?

 

There are two S modes which might be confusing you.

The red instrument cluster is from the Sport driving personality. You cycle through by pressing the drive mode, comfort=blue, normal=grey, sport=red, etc. This changes power steering strength, gas pedal throttle mapping, transmission shiftpoints, active noise cancellation, and on adaptive suspension models it changes the shock stiffness.

Separately there is the sportshift transmission mode. You press the D a second time and it toggles between sportshift and regular automatic transmission. This is the D vs S in the instrument cluster. Sportshift relies on you to use paddles to change gears. It will only change on it own if the rpm goes too high or two low, some people don't know the paddles are intended and just think this mode is intended to shift late. Also sportshift is usually the only way to force first gear for towing, since the car normally starts from a stop in second gear.

It is possible that tapping a paddle may also switch you into sportshift mode, I never tried but it would make sense, and might be accidentally hit while turning the wheel causing unexpected flips to sportshift.

 

Thank you so much for replying and I did not know about pressing D twice. It is entirely possible that subconsciously I was pressing on D on a red light stop when the car was already in D and that was causing the drive mode to go into S. I will keep an eye on it and may be this was the reason and I was freaking out over nothing.