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Discussion Starter · #1 ·
I've had the 08 MDX for a little over a month now. I have the maintenance records contained in the Carfax report, but nothing else, so I am in the process of taking care of those items that will ensure my MDX remains trouble free.

From everything I have read here, one of the must do items is a transmission fluid change, so I purchased 12 quarts of Acura transmission fluid from a seller on E-bay for $90 including shipping. The seller also included three drain plug washers with the 12 quarts of fluid.

I did the 3 X 3 trans fluid change over the past three days. In the case of my vehicle it was actually closer to a 3.5/4 X 3, so it was good that I had 12 quarts. Judging by the pressure required to initially remove the drain and filler plugs and the amount of debris initially found on the magnetic drain plug, I am fairly certain that this was the first time the trans fluid had been changed in the 58,000 miles this car has been driven. When I measured the fluid removed after the first drain it was exactly 4 quarts. I replaced it and drove the car approximately 80 miles. The difference in the transmission performance was immediately apparent. The shifts were much crisper and the overall performance was much smoother. I drove the car approximately 30 miles between the second and final drain and fill cycles. While the transmission performance improvement was not as dramatic after the second and third drains and fills as it was after the first, it was noticeably better with each successive change cycle.

I was impressed enough with the difference that this simple and easy maintenance item made that I am thinking about performing a single drain and fill (3 X 1) after 25,000 miles.
Tom
 

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I would agree that keeping the transmission maintenance up in these vehicles is a Great idea! I keep a case around and do a single 4x1 drain/fill each year on 2nd oil change as i have a trans cooler that empties out with opening the trans drain bolt. "Eneos" the company that developed the ATF DW-1 for Acura has there own brand "Eneos import H" If you read the back you see it is for vehicles that use ATF-DW! It is half the price of Acura ATF DW1 which individuals should check out. Seems a small price to pay $21.00 a year to keep things smooth and have peace of mind.


http://www.eneos.us/products/eneos-import-series/eneos-import-atf/model-h/
 

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Good to know...wilsoncc!

Next, you can start shopping for the 3 tranny sensors, because they are $50 ea.

Easiest to change, is the one behind the drivers tire, #28610-rke-004
Next easiest, is the one on the firewall side of the tranny, up high, #28600-rkr-004
Finally, the one that you can see, on top of the tranny, drivers side, #28600-rke-004

Each needs a new washer #90471-pw7-a00 and will be torqued to 14 ft/lbs.

They all have fine aluminum threads and can be over tightened easily.
 

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Just had a transmission fluid DRAIN & REFILL yesterday on my 2009 MDX- definitely can tell that the engine runs much smoother afterwards!

stealership wanted $230 for this service (parts & labor)- had my independent mechanic (who's been saving me MUCHO money for many years!) do this for $73 out the door. :29:
 

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Why the sensors??

When you're driving and you can feel the tranny shift gears, you can minimize the feel of the "shift", by changing the sensors.

I did mine at 95,500 miles and could immediately "not feel" the shifting.

I clipped the following from an AcuraZine DIY on replacing the sensors:

"Your transmission fluid pressure is maintained using pressure sensor switches. These parts wear out over time and normally much sooner than your transmission's gears."

Here's the complete:

https://acurazine.com/how-tos/a/acura-mdx-how-to-replace-transmission-pressure-sensors-429444
 

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I have all 3 OEM sensors in my garage... Can sell them $100 shipped... If any interested pm me...
 

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Discussion Starter · #8 ·
Good to know...wilsoncc!

Next, you can start shopping for the 3 tranny sensors, because they are $50 ea.

Easiest to change, is the one behind the drivers tire, #28610-rke-004
Next easiest, is the one on the firewall side of the tranny, up high, #28600-rkr-004
Finally, the one that you can see, on top of the tranny, drivers side, #28600-rke-004

Each needs a new washer #90471-pw7-a00 and will be torqued to 14 ft/lbs.

They all have fine aluminum threads and can be over tightened easily.
Are these maintenance items or things that need to be replaced when they fail? What are the symptoms of bad transmission sensors?
 

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Are these maintenance items or things that need to be replaced when they fail? What are the symptoms of bad transmission sensors?
After changing the transmission fluid and driving it a few days, does the transmission still shift hard, jerk, or have a hard time down shifting?

If so, change your sensors.

Some owners add them to their 105,000 mile maintenance project.

I noticed a smoother shift pattern, after I changed the fluid 4 times, but I could still feel the shifting. I could easily tell when each shift occurred.

After the sensors were changed, I had to focus to feel the shifting.
It still does not like to down shift and I wish it was a six speed, but that's how Acura wanted it, after the 1st gen mdx complaints, of them (1st gen) being too sluggish and no pick up.
 

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Discussion Starter · #11 ·
After changing the transmission fluid and driving it a few days, does the transmission still shift hard, jerk, or have a hard time down shifting?

If so, change your sensors.

Some owners add them to their 105,000 mile maintenance project.

I noticed a smoother shift pattern, after I changed the fluid 4 times, but I could still feel the shifting. I could easily tell when each shift occurred.

After the sensors were changed, I had to focus to feel the shifting.
It still does not like to down shift and I wish it was a six speed, but that's how Acura wanted it, after the 1st gen mdx complaints, of them (1st gen) being too sluggish and no pick up.
I can still "feel" the shifts, but they are much smoother, and don't seem to be out of the ordinary and in line with other auto trans vehicles I have owned. The reason that I wanted to change the fluid was that after slowing to between 40-45 mph and at around 1,500 RPM, the transmission action felt a little odd, as though it needed to downshift but it wouldn't and there was a little bit of roughness to its action. That is completely gone now, and it readily downshifts from 5th to 4th where it used to remain in 5th. It disappeared after the first of the three drain and fill cycles.
 

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I would agree that keeping the transmission maintenance up in these vehicles is a Great idea! I keep a case around and do a single 4x1 drain/fill each year on 2nd oil change as i have a trans cooler that empties out with opening the trans drain bolt. "Eneos" the company that developed the ATF DW-1 for Acura has there own brand "Eneos import H" If you read the back you see it is for vehicles that use ATF-DW! It is half the price of Acura ATF DW1 which individuals should check out. Seems a small price to pay $21.00 a year to keep things smooth and have peace of mind.


MODEL H | ENEOS
Where can you buy this ATF for cheap? I looked around and the price seems to be close to DW1 from Honda/Acura.
 

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Are these maintenance items or things that need to be replaced when they fail? What are the symptoms of bad transmission sensors?
The pressure switches aren't maintenance items recommended by Honda/Acura. However, the switches do wear out and lose their calibration over time, so they affect when the transmission decides to carry out a shift. Some owners decided to change out the switches as their own maintenance item, for the purpose of improving/restoring the shifting of the transmission.

As for the symptoms, here's one that you mentioned yourself:

The reason that I wanted to change the fluid was that after slowing to between 40-45 mph and at around 1,500 RPM, the transmission action felt a little odd, as though it needed to downshift but it wouldn't and there was a little bit of roughness to its action.

Why the sensors??
The switches sense the pressure in their respective fluid lines inside of the transmission. Once the fluid in that line reaches a certain pressure, the switch sends out a signal, which I guess goes to the transmission control unit. I believe that the TCU then sends a command to the solenoids, which do the shifting. If the switches start to operate far beyond their designed range, it can affect torque converter clutch lockup and results in a "shuddering" effect when changing gears under certain conditions.

Someone had cut open a pressure switch to take a look at its construction. Inside was a disc, which would flex as the fluid pressure pushed up against it, activating the switch. When new, the disc flexes at the correct fluid pressure. I believe that over the thousands of cycles that the disc flexes, the material it's composed of undergoes work hardening. As a result, the switches would not function within their specified pressure range.

Fluid changes and pressure switch replacement became popular fixes among owners for a few reasons: they are relatively cheap compared to other fixes; these fixes aren't too difficult for the DIY type; and they typically solved most of the transmission shuddering experienced by the owners.

If you have some time, read through this thread on Acurazine:
https://acurazine.com/forums/third-...nversation-my-transmission-builder-tl-721508/
 

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Discussion Starter · #17 ·
The pressure switches aren't maintenance items recommended by Honda/Acura. However, the switches do wear out and lose their calibration over time, so they affect when the transmission decides to carry out a shift. Some owners decided to change out the switches as their own maintenance item, for the purpose of improving/restoring the shifting of the transmission.

As for the symptoms, here's one that you mentioned yourself:






The switches sense the pressure in their respective fluid lines inside of the transmission. Once the fluid in that line reaches a certain pressure, the switch sends out a signal, which I guess goes to the transmission control unit. I believe that the TCU then sends a command to the solenoids, which do the shifting. If the switches start to operate far beyond their designed range, it can affect torque converter clutch lockup and results in a "shuddering" effect when changing gears under certain conditions.

Someone had cut open a pressure switch to take a look at its construction. Inside was a disc, which would flex as the fluid pressure pushed up against it, activating the switch. When new, the disc flexes at the correct fluid pressure. I believe that over the thousands of cycles that the disc flexes, the material it's composed of undergoes work hardening. As a result, the switches would not function within their specified pressure range.

Fluid changes and pressure switch replacement became popular fixes among owners for a few reasons: they are relatively cheap compared to other fixes; these fixes aren't too difficult for the DIY type; and they typically solved most of the transmission shuddering experienced by the owners.

If you have some time, read through this thread on Acurazine:
https://acurazine.com/forums/third-...nversation-my-transmission-builder-tl-721508/
Thanks for that. In my case, the fluid change removed all traces of the symptom that I was experiencing, to the point where I cannot replicate it even when I attempt to. At the same time, I can see myself at least obtaining a set of these to have on hand. Luck favors the prepared.
 

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Where abouts in the burbs are you. I'm a little north-Mukwonago, WI.
Get up here much?
I can't Pm....not enough posts.
I am on Cass ave and I-55 and don't really go north...
 

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