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I have an '03 X ~110k and my trans has been slipping & shuddering in 1st (unrelated) but I also noticed slipping in the 3rd upshift as well. I have also been plagued by harsh downshifts & jerky upshifts. I decided to change out the transmission switches / sensors in an effort to alleviate some of my issues. (btw.. I don't have AT DTC's). The result has been smooth downshifts & upshifts. My 3rd gear is much smoother and shifts firmly without slipping / revving. My 1st gear is still slipping but I knew the swap wasn't going to cure it. This DIY is good preventative maintenance to slowly failing pressure sensors going out-of-spec and not maintaining appropriate line pressure.
Highs
Easy - 1.5 hrs, < $100
Lows
None unless spending $100 is too much for your budget.
Tools
2 x Pressure Switch / Sensor washers / gaskets 90471-PW7-A00 #17 (optional) ~$2 each
Extra splash guard tabs 91503-SZ5-003 & 91501-S04-003 (recommended) ~$1-2 each
ATF (recommended) - price depends on what you use, I recommend Z1 w/ accelerated change intervals.
^ acuraoemparts
2001-02 MDX Owners
Btw.. if you own a 2001-02 MDX and you want to change out the pressure switches / sensors as well you have it much easier. Your transmissions were adopted by the 3G TL (2004-06) which there's already a DIY. On a related note, the 03-06 MDX transmission was adopted by the 07-08 TL with some tweaking including the addition of a pressure switch for the 4th gear. The Aziner (sixsixfour) who created the TL DIY thread put in the incorrect (yet correctly spec'd / same spec) switches, the P/N's he used to do the swap are the actual P/N's to the 01-02 MDX AT's. You can probably use the same ones used in this DIY as well. The only difference is the body of the switch / sensor is stepped while the other is flat. https://acurazine.com/forums/showthread.php?t=729149 <--- Click Link
Step 1: Strip it down
Unfortunately for us, we need to remove the intake tube, which is why I recommend doing an ATF drain & fill. I did a drain & fill before the swap so I don't have pics of it included. Anyways, take off the engine cover to get to the intake tube. When you remove the intake pipe, unbolt the filter housing first to give you some room to maneuver. Loosen the throttle body clamp, then use pliers / channel locks to remove the spring clamp on the header intake pipe / breather and slide it back. You should now be able to flex the intake pipe off and push it back from the filter housing & throttle body.
The service manual says you need to remove the battery, battery tray & pan to get to the 4th gear pressure switch but it's not necessary. I removed them but you can save yourself some time by skipping that step.
Step 2: Remove 4th Gear Pressure Switch / Sensor
The service manual says you need to remove the shift cable which is why you are required to remove the battery tray. Unless you're going to adjust the cable, it's unnecessary. You only have to loosen the top bolt of the wire harness bracket in order to get access to the 4th gear pressure sensor.
Unplug the connector first by pushing in the clip and then unbolt the top bolt (marked in blue) on the wire harness which pushes against the pressure sensor / switch. You should now be able to slide your 22mm deep neck socket over the pressure sensor. Remove it and then carefully clean off the area while avoiding contaminating the inlet before installing the new pressure sensor & washer / gasket. I just took a shop towel sheet and sprayed the sheet with some brake cleaner to clean it up.
New vs. Old
Dirty
Clean
Step 3: Install the new 4th Gear Pressure Switch / Sensor
Do not overtorque it! Place the new sensor & gasket in, and thread it in gently. Torque it to 14 ft.lbs.. only! Secure the connector over the new sensor & secure the harness bolt that you removed.
Reassemble all the removed parts, battery, intake tube. Make sure you put everything back and tap all the secure points down - intake housing bolt, throttle body clamp, header breather tube & spring clamp, engine cover clips, etc..
Step 4: Remove driver's side splash shield
This requires some tab removal from the driver's side fender / wheel well and two 12mm bolts if I remember correctly. The way you remove the tab is to use a flathead to pop out the neck; pull the neck all the way back and the tab / clips should come out easily. I had 4 bad clips that I couldn't replace due to dry rot, which is why I recommend buying add'l clips.
Step 5: Remove the 3rd Gear Pressure Switch / Sensor
Once the splash shield is out of the way, you should clearly see the sensor behind the subframe support & front motor mount. Lay some shop towels down because some ATF will leak out (maybe 2-3 ounces). Unclip the connector & remove the sensor. Clean up the area and ATF before installing the new 3rd gear pressure sensor / switch.
Step 6: Install the new 3rd Gear Pressure Sensor / Switch
Install the new pressure sensor. Remember.. Only 14 ft.lbs of torque! Clean up any residual ATF on the case with some brake cleaner. Put the connector back on and put the splash shield back up with the appropriate clips and your done.
Broken Tabs / Clips
Recommendation: Change ATF
Since you're already in there.. access to the ATF fill bolt & drain bolt are cake. The ATF fill bolt is on the top of the image below, painted blue and is marked ATF on top. Looks like a 22 or 24mm socket size. You'll need a funnel. I didn't host a picture of the drain bolt but it should be female 3/8" drive bolt, bottom of the case and will probably be marked with paint as well. I'll host pictures of both later on tonight.
Well that's it.. If I missed something let me know. I hope that helps some of you out.. and if you're still wondering WTF? Here's some reading material.
It's been a couple of months now and it shifts beautifully. I'm much happier. It still slips in 1st before upshifting but other than that.. it's like new again. No jerkiness or spotty rpm's / hydraulic pressure while cruising.
You'll need to remove the intake.. I'm sure with the right extensions it's possible but it would be a total pita.. you'll end up dropping something.. then end up removing the intake anyways.
need to do this. Just bought my girl a 04 touring and i too a have a small shudder and slip in 1st and hard shifts after that. Thanks for the write up.
Last edited by InFaMouSLink; 10-21-2012 at 11:44 PM.
What do you suggest now? I also have that rpm issue where if i let go of the gas, my rpms drops way below 1K. slight slipping in first and rough transitions.
Let me start by saying thanks to the OP for this thread. Took my '06 X to the dealer to find out what was causing an intermittent blinking D5 light and found out it was the 3rd pressure switch. Armed with this write-up, I told them not to bother replacing it, that I'd go ahead and do it myself (and figured I'd just do both the 3rd and the 4th while I was at it), and it was pretty straightforward.
FWIW, when I went to change out the 4th, I found that it was mounted sideways. I guess they re-positioned it for the 2006 model.
That made it a little more of a pain to get in and out. I found a long-handled 22mm box wrench really convenient for getting it out, but it was too much trouble to get a 22mm deep socket + a 1/2"-to-3/8" adapter + my 3/8" torque wrench in there, so I went ahead and picked up a 1/2" torque wrench. I probably could have just tightened it with the box wrench, but I was paranoid about over-tightening it, and I don't really need much of an excuse to buy a new tool
Great DIY. One of the best series of photos I've seen for this task. I get the sporadic flashing D5 light which is attributed to these pressure switches too and this thread will most definitely make my life a little easier!
I have done plenty of research on this but so far the transmission drives fine when put in d4. when we put the trans in d5 and driving at a constant speed, you can feel it almost downshift then upshift simulataneosly. I'm guessing this is the torque converter locking and unlocking. I had planned on replacing the 3rd and 4th pressure sensors but I was hoping someone could help shine some light on this.
i read the bulletin about the torque converter and I am really hoping replacing the TC and performing the pgmfi update is not the fix.
I had the D5 flashing issue on my 05 MDX and replacing the 3rd and 4th switches fixed the issue about a year ago and now it is back. Replaced the tranny temp sensor which I had found could be the issue, but no luck.
Are there other switches that could go bad and need to be replaced?
Let me start by saying thanks to the OP for this thread. Took my '06 X to the dealer to find out what was causing an intermittent blinking D5 light and found out it was the 3rd pressure switch. Armed with this write-up, I told them not to bother replacing it, that I'd go ahead and do it myself (and figured I'd just do both the 3rd and the 4th while I was at it), and it was pretty straightforward.
FWIW, when I went to change out the 4th, I found that it was mounted sideways. I guess they re-positioned it for the 2006 model.
That made it a little more of a pain to get in and out. I found a long-handled 22mm box wrench really convenient for getting it out, but it was too much trouble to get a 22mm deep socket + a 1/2"-to-3/8" adapter + my 3/8" torque wrench in there, so I went ahead and picked up a 1/2" torque wrench. I probably could have just tightened it with the box wrench, but I was paranoid about over-tightening it, and I don't really need much of an excuse to buy a new tool
That's an '07 trans design, have you ever had the trans replaced? There should be one more 4th gear pressure switch on the other side of the fill bolt.
It should be noted there is a THIRD pressure switch on late model first gen MDX's. I don't know which year they changed the transmission, but mine is a 2006. I was confused when I went to do this project, because my upper transmission pressure switch was mounted horizontally, not vertical, and yet the parts diagram also showed it being vertical, just like the pictures in this thread. However, after doing some digging I found the parts diagrams are often wrong, even when you search under a 2006. I eventually found the below parts diagram correctly showing the layout:
As shown on this diagram, there is a third pressure sensor on the upper rear of the transmission, part number 28600-RAY-013.
Thanks to everyone who added information to this thread. It was really long but valuable.
The 2 Acura sensors have gotten pretty expensive - $60 each. Interestingly they've also been superseded with new part numbers, from Washimiya instead of Texas Instruments. Does anyone have feedback on using quality aftermarket parts for these specific items? I've used Standard Motor Products (Intermotor) a good bit on other parts, and have always been satisfied. I know Wells is a big and well regarded aftermarket company, but I haven't used their products. All the options below I've found at about $35 each.
For 28610-RAY-003 RockAuto lists
Standard Motor Products PS497
Wells Vehicle Electronics 1S7427 Under the new part number 28610-RKE-004 RockAuto lists
Rostra 501174 (never heard of them)
Standard Motor Products PS451 (that's no accident, it didn't cross back the same)
Wells Vehicle Electronics 1S7427
For 28600-RAY-003 RockAuto lists
Standard Motor Products PS510
Wells Vehicle Electronics 1S7426 Under the new part number 28600-RKE-004 RockAuto lists
Only Rostra 501060
If I do this, I'm tempted to go with SMP. The Rostra pictures don't seem they put much care into the finish, which concerns me if they do the same with the internals. But I don't know if I go SMP, should use both the old cross part numbers PS497/PS510, or use the one that is updated PS451 even though there isn't an updated version for the PS510.
Updated part numbers usually mean the part had to change slightly but should be similar; main difference between the different switches is the pressure they activate. Some are lower around 28 PSI, others are higher at nearly 40PSI. I'd honestly stick to OEM; try acuraoemparts.com and use coupon code "acurazine" for 5% off.
acuraoemparts.com is $124.45 for the 2 switches with 5% off and shipping. At that price I probably wouldn't do it unless I had the symptoms that mean damage is occurring. If it goes before one of the many other things that can make the car uneconomical to repair, I'd just send the car to the junkyard. One can easily over-preventative maintain and overspend on an old car. I'm already planning to replace the front compliance arms due to bushing rot and vibration ($240 with the associated parts), updating the Nav because I like it as a backup and its from 2006 ($100). And my seat leather is tearing but I'm trying to limp it along with big adhesive leather patches.
But for ~$70 from SMP I'd be willing to be the guinea pig, if no one else has tried a big name aftermarket pressure switch and had problems. I tow with the car so having those switches in calibration would be better for the transmission. Frequently the big aftermarket companies can have as good or better quality than OEM. But there are cases where only the OEM works best. I also had never heard that ATF type F would reduce transmission wear in these cars until I read either in this thread or one of the links off it. I used to drive manuals so I'd prefer as firm as shifts as possible as long as there isn't clunking. So I will probably switch to that slowly.
I was suspicious that the change in part number was just a change in supplier from Texas Instruments to Washimiya, but could be an actual small part revision. I did finally find the Standard Motor Products company parts catalog online. For a 2006 they say it is PS497/PS510. They say the PS451 is only for 2001-2002 MDXes. The PS497 can be used on MDX 2001-2006. So something about the multiple cross compatibility exchanges from Acura to SMP to RockAuto is messed up.
I just discovered that my 2006 has the upper pressure switch (middle circled switch) mounted horizontally instead of vertically. So based on Fridge73 post, I should find a 3rd switch. I've spent about an hour looking 3 different times, and I haven't been able to find it. That area is buried under the edge of the intake, and would be a monster to change it. Assuming it actually exists, since Acura claims it doesn't based on the service manual and the part diagrams I've found, I'll continue looking or may try contacting Acura, not that it is likely to get me anywhere. I don't think it would be a good idea to replace 2 of 3 if it exists, since it sounds like they work as a system.
There is a data plate next to the ATF fill bolt that reads: BDKA-8009947, and then there is a 6 digit number below it. I assumed that's the transmission dataplate with model number and serial number. BDKA-8009947 gets zero results on Google. I've never had that happen with any part on a car I own. I'm starting to wonder if my car is a transitional unicorn that Acura didn't properly document.
Has anyone been able to confirm the extra pressure switch exists and what it does? Is it a redundant switch to try to catch if the other switches are drifting to throw a code? Or does it have specific functionality related to the other switches?
Acura has weak service manuals, and horrible accuracy on their parts catalogs. I'm getting real sick of Acura's Engineers and Tech Docs people. I can't count how many mistakes and incomplete documentation I've found, and I've owned this car barely a year. I never found an outright mistake in my Pathfinder service manual.
acuraoemparts.com is $124.45 for the 2 switches with 5% off and shipping. At that price I probably wouldn't do it unless I had the symptoms that mean damage is occurring. If it goes before one of the many other things that can make the car uneconomical to repair, I'd just send the car to the junkyard. One can easily over-preventative maintain and overspend on an old car. I'm already planning to replace the front compliance arms due to bushing rot and vibration ($240 with the associated parts), updating the Nav because I like it as a backup and its from 2006 ($100). And my seat leather is tearing but I'm trying to limp it along with big adhesive leather patches.
That is expensive but may be worth it in a bit when you do fresh fluids again for better crisper shifts and to prolong life of clutches. Cheaper may be the exact same! Nav update will not update the UI at all. Look into something that can either mirror to the nav or add some audio input such as GROM/ USASPEC/ Or Isimple. I have Isimple in my MDX and 3G TL and like it very much. Was about $150 and self install to have ipod connectivity and waze audio through speakers. As far as leather Lseats.com and a few other sites sell MDX replacement bottoms for a good price.
But for ~$70 from SMP I'd be willing to be the guinea pig, if no one else has tried a big name aftermarket pressure switch and had problems. I tow with the car so having those switches in calibration would be better for the transmission. Frequently the big aftermarket companies can have as good or better quality than OEM. But there are cases where only the OEM works best. I also had never heard that ATF type F would reduce transmission wear in these cars until I read either in this thread or one of the links off it. I used to drive manuals so I'd prefer as firm as shifts as possible as long as there isn't clunking. So I will probably switch to that slowly.
Type F can cause damage in honda transmissions as they are very sensitive to friction modifier level. You can use some Type-F but do not exceed 2 quarts. Use Honda/acura DW-1 fluid (the off brand stuff is not the same as per multiple oil analysis done at bobistheoilguy forums). Your best bet is to install a trans cooler and an inline filter to help reduce trans temps as that is what kills the honda trans fluid and clutches, HEAT!
I was suspicious that the change in part number was just a change in supplier from Texas Instruments to Washimiya, but could be an actual small part revision. I did finally find the Standard Motor Products company parts catalog online. For a 2006 they say it is PS497/PS510. They say the PS451 is only for 2001-2002 MDXes. The PS497 can be used on MDX 2001-2006. So something about the multiple cross compatibility exchanges from Acura to SMP to RockAuto is messed up.
Rock auto and acura's parts compatibility are hell in a handbasket. Mirror motors from 2004 TL swap with 2008 and vice versa but you cannot buy 2004-2006 motors anymore, but they are not listed as interchange... So STUPID!
I just discovered that my 2006 has the upper pressure switch (middle circled switch) mounted horizontally instead of vertically. So based on Fridge73 post, I should find a 3rd switch. I've spent about an hour looking 3 different times, and I haven't been able to find it. That area is buried under the edge of the intake, and would be a monster to change it. Assuming it actually exists, since Acura claims it doesn't based on the service manual and the part diagrams I've found, I'll continue looking or may try contacting Acura, not that it is likely to get me anywhere. I don't think it would be a good idea to replace 2 of 3 if it exists, since it sounds like they work as a system.
There is a data plate next to the ATF fill bolt that reads: BDKA-8009947, and then there is a 6 digit number below it. I assumed that's the transmission dataplate with model number and serial number. BDKA-8009947 gets zero results on Google. I've never had that happen with any part on a car I own. I'm starting to wonder if my car is a transitional unicorn that Acura didn't properly document.
Has anyone been able to confirm the extra pressure switch exists and what it does? Is it a redundant switch to try to catch if the other switches are drifting to throw a code? Or does it have specific functionality related to the other switches?
Acura has weak service manuals, and horrible accuracy on their parts catalogs. I'm getting real sick of Acura's Engineers and Tech Docs people. I can't count how many mistakes and incomplete documentation I've found, and I've owned this car barely a year. I never found an outright mistake in my Pathfinder service manual.
So there are different "models" of trans depending on year:
2001/2002- MGHA/BGHA
2003- MKDA
either in 04, 05 or 06 switch was made to what you posted "BDKA" trans code.
That is expensive but may be worth it in a bit when you do fresh fluids again for better crisper shifts and to prolong life of clutches.
I don't know the history of my transmission. I think it wasn't maintained. Because worn transmissions sometimes don't like big changes, I've been doing one drain and fill at every 6k oil change. It's on the 2nd change. Each change the sifts seem a little firmer. I could tolerate much firmer shifts than the average driver, having come from 25 years of driving a manual. I'm planning to do the switch change soonish before the next oil change, since you only lose a few ounces of fluid.
Originally Posted by csmeance
Nav update will not update the UI at all. Look into something that can either mirror to the nav or add some audio input such as...
Yes I was aware update doesn't change UI. This is my first car with navigation, but I've been using Google Nav for 10 years. I have grown to like the moving map in the car separately, without having to fart around with my phone. I wanted to update to remove some unverified road banners, and correct daylight savings time error. Some day I may replace the radio with an Android head unit. I have a Roav Viva connected to the car to send phone audio through the speakers, and use Alexa. I've found its a little bit of a pain. I don't use it unless I'm the passenger and my wife is driving.
Originally Posted by csmeance
Lseats.com and a few other sites sell MDX replacement bottoms for a good price.
Lseats.com says site not found for me. Is it maybe Lseat.com? I see they have Acura seat covers, but not currently advertising MDX covers. I'll contact them when I'm ready to do it. Thanks. I'm not sure I'm up to the tediousness of replacing the covers myself and trying to repack some foam. I hated doing the leather on the console. I had found theseatshop.com previously but $220 for each bottom was just too much for me.
Originally Posted by csmeance
Type F can cause damage in honda transmissions as they are very sensitive to friction modifier level. You can use some Type-F but do not exceed 2 quarts.
Interesting, that is opposite of what a couple other people on another thread on this forum said - that the friction modifiers soften shifts for consumer taste at the expense of friction longevity. But if you are OK with very firm shifts up to 100% Type F will make your Honda transmission last longest.
Originally Posted by csmeance
Use Honda/acura DW-1 fluid(the off brand stuff is not the same as per multiple oil analysis done at bobistheoilguy forums). Your best bet is to install a trans cooler and an inline filter to help reduce trans temps as that is what kills the honda trans fluid and clutches, HEAT!
So far I've been using Idemitsu Type H (who manufactures DW-1 for Honda). I was going to switch to Valvoline Max Life based on a bunch of glowing recommendations on MDX, Pilot, and Oddessy boards back when these transmissions were a flaming dumpster fire. I've also been using LubeGard Platinum based on the same.
Yes heat and dirty fluid will kill most auto transmissions quickly. That's one reason I've steered clear of them for 25 years. I got tired of roasting the Torqueflite transmission in my Scout every 30k miles after the first rebuild lasted 100k. I put a Hayden 679 cooler on the Acura. It is their biggest cooler designed for motor homes. I also put a Magnefine filter on it. I can't believe that Honda made the internal filter non-serviceable without dropping the transmission. I consider that professional negligence.
Originally Posted by csmeance
Rock auto and acura's parts compatibility are hell in a handbasket.
Noted. Based on SMP catalog and history I would still lean towards trying them. But I sent AcuraPartsNow.com a question asking what's up. They quickly replied that some cases were manufactured like mine with horizontal placement, but it should not have a 2nd 4th clutch pressure switch. That was such great customer service, I believe they deserve my business even if Honda's price is excessive for the part. I wonder if Fridge (above) actually found that 3rd switch on his 2006 transmission. Or if that part diagram was from 2007 and looked similar but not the same confirmed transmission part number or configuration as his.
Interesting aside, I believe it's McKinsey Consulting has been going around to car manufacturers proposing they analyze the retail price of their service parts, to jack up the price - not to a level in relation to the manufacturing cost and reasonable profit, but based on the customer's perception of the parts complexity and therefore their maximum expected price tolerance.
I know this is how capitalism works. But it is so brazen to do with your product support, versus the initial product purchase. And it's not like Honda has a leg to stand on in building the most durable parts. They've screwed up repeatedly, especially recently with their declining average reliability. Though they've done nothing as bad as many American manufacturers or Nissan under Ghosen.
thank you for the write up and it was nice,d I have to say that I am sorry for my earlier post about finding the 4th gear switch on the side. I have been stuck, for some reason I still
have not been able to locate the 4th gear switch. I have removed battery, intake, breather, but left battery plate. I found the 3rd easy but and already replaced, hopefully did not get them mixed up, I was reading somewhere that the tan goes on top but I put it on the bottom so might have to switch them around. Okay back to getting some help, I can not seem to find location of the 4th gear switch, could someone please help me, 2001 mdx acura 4wd
thank you for the write up and it was nice,d I have to say that I am sorry for my earlier post about finding the 4th gear switch on the side. I have been stuck, for some reason I still
have not been able to locate the 4th gear switch. I have removed battery, intake, breather, but left battery plate. I found the 3rd easy but and already replaced, hopefully did not get them mixed up, I was reading somewhere that the tan goes on top but I put it on the bottom so might have to switch them around. Okay back to getting some help, I can not seem to find location of the 4th gear switch, could someone please help me, 2001 mdx acura 4wd
Sorry I didn't see this in time to take pics. Mine is a 2006 and it has the upper pressure switch pointing horizontal into the case. I understand the pre 2005 upper pressure switches pointed vertical down into the case. So I could recognize the pressure switch to point to it in a pic, but only for later model years.
For others that come across this thread, the lower pressure switch was very straightforward to replace, especially if you've had the splash guard off before. Be certain to get plenty of replacement push pins. They are much cheaper on Amazon. I broke 5 of them even with push pin pliers. I've removed the splash guard before without push pin pliers. After using the pliers, I'll never do it again without them. Those pliers are worth $100, but you can get a pair for $15. It's indescribable how much easier it makes removing the splash guard. The only slightly difficult part is getting a torque wrench in there to tighten the pressure sensor. I use a torque wrench on everything. Mine is just barely longer than a 3/8" drive, maybe 12". I could only get it into a position where I could ratchet it 1 click at a time.
Doing the upper pressure switch, at least for cars with the sensor mounted horizontally, is a monster. I don't have enough 4 letter words for Honda engineers. There is no room to get your fingers in that area unless you are a 5 year old. But you need the grip strength of a 30 year old weightlifter to pinch the connector and pull it off. It was much easier when I figured out 2 things - aside from removing your air filter intake pipe to it, you must also remove the battery and battery splash guard. You do not have to remove the battery tray. You must also remove the 2 nuts that hold the shift cable bracket. Once you remove those, you can lift the bracket off the studs and move it to the right about an inch without removing anything else related to the shifter assembly, to get enough room to remove and replace the sensor. Those nuts should be tightened to 10 newton meters when replaced.
10-07-2009, 04:10 PM
Great DIY. One of the best series of photos I've seen for this task. I get the sporadic flashing D5 light which is attributed to these pressure switches too and this thread will most definitely make my life a little easier!
Aftermarket pressure switches
