Magnus

For the past 10,000 miles (I'm at 108,000 now) my 2001 MDX transmission misses shifting into 3rd gear when I accelerate slowly from a stop. It seems to completely disengage (going to “neutral”) when it leaves 2nd gear. When this happens, I let off the gas, and the transmission usually goes on to 4th gear (or I drop to 2nd to boost my speed first).

I recently took the MDX to the Acura dealer for a timing belt replacement, and asked them to check the transmission. They found no codes, and the transmission shifted normally on a test drive, and they told m to return when I had trouble again.

That has been my story for the past year, until today... when the transmission seemed to miss 3rd frequently... and so I gave it a little test...

I had just come out of a 35mph school zone on a 50mph road, when I floored the MDX and it downshifted to 2nd (?). Immediately the “check engine” light came on and the D5 light began flashing. When I released the gas, the transmission remained stuck in 2nd. Shifting to N and back to D5 had no effect. Stopping at a traffic light had no effect.

I pulled over and shut off the engine, and pulled the key. Then I restarted the engine. The D5 light was not flashing, however the “check engine” light remained on. I drove off and again 3rd gear missed the shift. I let off the gas and 4th gear caught and I made it back home

I have an appointment with the Acura dealer tomorrow. What am I facing?

007Acura

sounds like some thing is wrong... Hopefully they will find the codes, if thats your original transmission it may need to be replaced

mdx_1976

Potential replacement of transmission especially if the tech finds any metal from grinding in the transmission oil.
If there are no codes found, drain the transmission oil and have that checked out.
Let's know how it goes for you. Good luck.

csmeance

more than likely it's a faulty 3rd gear pressure switch which has caused some damage to the internals. Have you been changing the fluid at regular intervals? If so what interval? What fluid?

PiratesPalm

I have an 01 MDX with 110K miles on it. I bought the car a few months ago with 90K miles on it. The trans was fine until the car heated up, then would start acting quirky, not shifting into 3rd gear it would flare up, sometimes would feel like slamming on the breaks or downshifting. I kept driving it like that then suddenly it all cleared up and drove perfect for a couple months. The car had beed sitting a long time before I bought it.

When it starting acting up again after driving fine for a couple months. It would flare up when shifting into third gear, then there was a mild vibration when shifting into third gear as if not catching correctly. Now it doesn't shift into third gear at all.

At first the D5 was blinking and engine light came on so I pulled the code and it was 0730 incorrect gear ratio and 1739 faulty 3rd gear pressure switch.

So, before spending a lot of money as I don't have it, I did some research online and saw a lot of different responses to this same problem. So, I spoke with a person at a trans shop and he said the first thing he would do is replace the 3rd gear pressure switch, so I did $70 at the dealer, I went home, put it on, and disconnected the battery for 10 minutes to reset the computer and clear the codes.

Then I drove it and the same thing happened, when it gets to the point where its supposed to shift into 3rd gear, it just revs or flares up in rpm. No matter how fast or slow I got to try to get into 3rd gear, it just doesn't. I have to got from 2nd to 4th in order to move the car.

I also had the problem of it sticking in 2nd gear to the point where i had to shut off the car to get it to shift into the other gears.

So, after changing the 3rd gear pressure switch I got the same problem and amazingly the same errors codes again 0730 and 1739. It still says the 3rd gear pressure switch failure, even though I just put a new one on there.

So, the next day I decided to tear the whole car apart and I pulled off all of the gear and clutch pressure solenoids...all 6 of the units on the tranny. I got electrical testing charts from the dealer to measure the ohms and check for the clicking and functionality of each unit. They all tested okay. One of the the solenoid valve c 6.2 ohms instead of about 5.5 ohms which its supposed to be, but i was told it was close enough. I don't know.

So, basically they all checked out okay, except maybe that one might not be within range.

I even pulled off the 3rd gear pressure switch and ran the car in 3rd gear briefly to blow out any clogs in the line, but the fluid poored right out, so the switch is getting fluid to it.

I also bought a replacement filter, the one that goes on top of the engine and replaced that, the oil jet filter, it didn't make any change either.

I also tested the voltage at the 3rd gear pressure switch connector harness side and i got 12 volts when grounding it, so the circuit is good from the pcm to the switch.

I don't know what else to do at this point. My feeling is that the trans is still okay, i may be wrong, but all the gears shift fine except the 3rd just revs, like something's not engaging it.

I think I need to test the pcm more, its kind of hard to get to underneath the dash on the floorboard in the middle.

The testing flow diagram I have which tells you if yes go here, if no go there, doesn't tell me if something is bad if it is yes or no on the diagram, it just says go to another step and try that. for example it says to check from the back of the harness side of the pcm connectors D13 and B20 or B22 for continuity, if yes go to step 3 if no go to step 16, etc. it does'nt tell me if its supposed to have continuity or not.

some of the test i couldn't do because it says to put the car on jackstands and run it and then measure the voltage.

If anyone has had the same experiences or problems that I have had and has gotten their's fixed, please tell me what the problem was and what you had to do to get it fixed.

Also, if anyone knows how to test the 3rd gear pressure switch, please tell me how. the info i have says to ground the prong on the switch to the frame or ground and it should give a reading of 10 M ohms or higher but i don't get a reading.

So, what i did was take it off the car, and touched the prong to the side of it and got no reading again. Then I used a small screwdriver to push in the plunger inside the switch and measured the ohms while doing it and it quickly gave me a reading varying from 3 to 7 M ohms but each reading always went to 0.0. I don't know if i'm testing it correctly or not. This is another reason why I went and bought the new switch, which ended up not making a difference and giving me the same error code again.

If anyone has had the same experiences or problems that I have had and has gotten their's fixed, please tell me what the problem was and what you had to do to get it fixed.

Thanks, piratespalm@yahoo.com

UTAH MDX

p0730 incorrect gear ratio code is the death code I work at a honda dealer (for many years) and have never seen a pressure switch wiring or pcm be the problem sorry its transmission time i have done several million v6 transmissions it seems like

dominik331

UTAH, just sent you a PM. Please Check