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Discussion Starter #1
Hello All:

I have a problem and I am hoping for some insight. I bought my 2003 MDX in about 2008 with 80K on it. From purchase, the transmission would pop out of gear in certain situations. Typically, it was in the winter or worse in the winter and when the car first starts up and is cold. If I would go over a speed bump where you take your foot off the gas it would pop out of gear. Another example would be in a parking garage where you accelerate slightly coming up the ramp, take your foot off and coast as you turn into the next ramp and hit the gas again. If you throw it down into 2nd while taking your foot off the gas, it would catch and go. I got used to this and learned in the winter to leave it in 2nd gear for the first couple miles.

Fast forward to today. Transmission finally died at 200K but I am not sure it was related to my problem. Could have been operator error on my part. Anyway, long story short, I have 4K in a remanufactured tranny and it is still doing the same thing. Tranny guys say the engine and tranny check out fine. Just wondering, any ideas what it could be? Thank you
 

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Let's be clear about something here.....Is the shift lever moving out of the gear you selected??? As in you placed it in D5, and when it "pops out of gear" the lever physically moves to "N"??? Does the light on the dash also change places? I assume this is what you are talking about.

This is odd because the position selection detents are in the transmission, not in the lever assemble. Does the shift lever move hard? Have you double checked the cable adjustment, and mounting points?
 

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Discussion Starter #3
I am pretty sure the shift lever stays in gear (actually, I keep it in 4th most of the time and not 5th). The shift lever definitely does not pop all the way to the "N" position. As for the lights on the dash, not sure. I know that sounds kinda silly; but when it happens I am usually reacting pretty fast to solve the problem while watching traffic. I will try to look next time.

Now, something I did not consider is this. Can it pop out of gear by just slightly moving to the right? As an analogy, kinda like a GFI circuit breaker can fool you into thinking it is not thrown because it may not move all that far when it trips??

Your Other questions:

Does the shift lever move hard? No
Have you double checked the cable adjustment, and mounting points? No and No.

The other issue is since the remfg tranny my daughter has been driving the car and she is the one reporting the malfunction. I took the car back last night and intend to drive it a couple weeks. So far, it has not popped out of gear on me.

Thanks!
 

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I understand not knowing what the dash light looks like, it is wise to focus on safety first.

A left of right movement of the lever in the D4 position should not cause any gear change. However that being said, it would enable the shift lever to move slightly in between gears. This could lead to a diagnosis of a shift cable slightly out of adjustment.

Keep us posted, and if you need any assistance I work in Aurora during the week, maybe I can help you out in person if you like.
 

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Discussion Starter #5
Thanks. More information than you need, but I was in the process of giving the car to my daughter who goes to school in Texas (up here for the summer). Bought a 2012 MDX for myself, a new tail light and headlights for the old MDX and a little rework of the paint on the front bumper (if you live out here you know the issues with "sand" (i.,e. small gravel) on the roads in winter); then the tranny goes (murphy's law!).

Since the tranny was replaced, the reports of slipping have come from my daughter who is visiting for the summer. I have not had the problem, myself; so I am driving the old 2003 mdx trying to see if I can replicate the issue. What I don't want is for her to take the car 1000 miles away and then have the problem show up.

Thanks for the help!

Douglas
 

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Was there ever an update on this? My '03 just started doing the same thing. Exactly as you described. Same scenarios.

TIA

Nick
 

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Discussion Starter #7
Update: It was not the transmission. It was never the tranny. It was a faulty chip. A pricey, faulty chip I think located just under the gear shift that sends signals to the tranny. Want to say the chip retails for about $1500. The tranny shop was able to get a chip "on loan" as we tested it out because we really were not sure that it was the chip. If you are in Denver, it is the ??AC Transmission shop at the corner of Colfax and I-70 just down the street from Planet Honda.

Sorry I cannot be more specific. Was a long time ago now. Just so you know, it drove the transmission shop crazy they were probably glad to see me go!

DT
 

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Thanks so much Douglas for coming back and posting the answer to this. My 2003 MDX is experiencing the same issue you described, and of course a tranny rebuild (twice) did not fix the issue. Of course, I think I just wasted $2800 on a tranny rebuild, and now I'll probably have to buy the chip too :(.

You said the chip is located under the gear shift - is it actually inside the tranny or between the tranny and the center console?
 

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There is no "computer" or "chip" besides the main ECU. There is a position sensor mounted on the outside of the transmission case. See item #11 on the following diagram:

https://www.acuraautomotiveparts.org/auto-parts/2003/acura/mdx-5-door/prem-trim/5-speed-automatic-engine/transmission-automatic-cat/at-oil-level-gauge-position-sensor-03-06-scat

It sends a signal to both the ECU and the Position Indicator on the instrument cluster to indicate what gear position is chosen by the shift lever. If all the indicator lights on the dashboard are working correctly at all times (i.e. not intermittent) your sensor is working OK.

It is also important that the shift cable be properly adjusted. To check, remove the center console so you can get to the shifter and cable. Pull the "U" shaped Lock Pin clip that locks the adjuster and cable end together. See below:





Rock the shift lever back and forth and then select a gear by pushing or pulling the cable. You need to be sure that the detent at the shifter and the trans are both settled in their resting positions. At this point, the U clip should fit easily back in place. If not, the cable needs to be adjusted. See diagram below:


 

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Bluepill, thanks for the response. After thinking about it more I started looking into the service manual and the only sensor I could find that matched the description of "under the gear shift was the 1st-hold switch (I still have no idea what that does).

I have never noticed any intermittent problems with the dash position lights, so I'll have to check the next time this happens.

I could try adjusting the cable in the meantime. Is the center console difficult to remove? I might also need a rear heater blower anyway, but I thought I needed to remove the seats to remove the center console.
 

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Discussion Starter #11
Hi. Sorry for the delay.

I am not a mechanic so I cannot respond to the comments re no chip / chip. All I can tell you is that the repair shop called it a chip I thought he said it was right under the gear shift. He lead me to believe that it was not in the tranny.

The shop I used was in Golden Colorado pretty much at the corner of I-70 and Colfax. The guy will probably remember me. You need to speak to the main guy / owner. This was a couple years back, but purdy she he won't forget this one.
 

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Thanks Douglas. I did look up that mechanic after your other post so I have the number and will probably try to call tomorrow, since it happened again today.

While I was out of gear, I remembered to check the instrument panel but noticed no flickering in the shift position and it was solidly on D5, so perhaps it's not my position sensor after all. Playing with the shift position (Trying to move it only slightly) didn't change the light either, so to me it looks like the shift cable is adjusted properly and the sensor is working. I would have spent more time playing with it but there was another car behind me.

Thanks all for the help.
 

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Well, good news. After months of dealing with this, the transmission place finally found the issue:

As it turns out, the shop replaced this transmission position sensor (mentioned above), and it still did not fix the issue.

I went back in and they dropped the transmission a 3rd time for debugging and found it was the "3rd gear sprag" that was the problem. They said they put the assembly on the bench, and the unit is only supposed to spin one way, but occasionally they were able to get it to spin the opposite direction. They also mention that this part was part of a large (assuming expensive) assembly before, but since last month it is now available to purchase separately.

It is now 3 weeks and 2500 miles later, and the problem is gone! Hoping this post will help future MDXers.
 

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I just bought a 2005 MDX with 127k on it as a 2nd car, it seems to be in great shape. I have noticed the car popping out of gear while sitting at a red light once, when the light turned green I hit the gas and the engine reved up and I went nowhere. I’m a little scared to drive it until I get this problem corrected. Since I haven’t owned the vehicle for very long, I don’t know how frequently this may occur. I came across these posts and they are some what helpful but people have posted different solutions, such as a chip, a sprag, or position sensor. I was wondering and possibly hoping for more detail or next steps I should take. It sounds like replacing the transmission is a waste and not a true solution. Should I take it to a basic mechanic, Acura dealer $$$ or a transmission specialist such as amco. I would also love to avoid the trial and error approach so if someone could explain the way to correct this problem I can then take that to the mechanic and have it fixed efficiently. I don’t won’t to just throw money at different parts so looking for some direction on what my next steps should be.
 
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