Majofo

Yeah, the D4 is definitely not the issue.

MetalGhost99

Any 2007 and 2008 TL owners have changed out theirs? If so and when. Because since we have the RL tranny in ours I would like to know how durable it is. Got mine at 33k miles and now has 78k miles on it and plan to replace mine at 105k miles when I do the plugs and wires. So far no problems with the transmission.

pwr2panda

I didn't really want to blame the D4 as it did clean up the shifts, but I guess I do drive in just auto a lot and am probably guilty of forcing the 4-2 downshift. It's just so odd how quickly the symptoms developed in a period of 1-2 days. It holds 1-2-3 fine, but 4th and 5th are iffy especially shifting under load (uphill).

I looked back on my service records as I remember getting the switches done sometime while I still had the car under warranty. Looks like the last time I had the switches (both 3rd and 4th) replaced was 10/2011.

So according to your plan of replacing the switches at least every two years, I was behind. Plus I did the complete 3x3 with the D4 from 8/2013 to 12/2013. Should have done the switches with the fluid replacement then.

My indy honda/acura mechanic didn't think the switches were a problem until they threw codes, but he's willing to replace them plus the trans filter ('05 TL). Could the 3x3 have clogged the filter from the "cleaning" detergents?

The car's gonna have the switches and filter replaced as well as 1x3. Any recommendation on ATF? Was planning on just honda DW-1. Thanks IHC. Edit:: hopefully one that I wouldn't have to wait to ship? Amsoil Type F in stock most places?

1KLRTOY

I would recommend using type F for the flush, preferably Redline racing

I hate cars

Type F is usually available at any auto parts store but it's marketed as a racing fluid lots of times so look for anything labeled racing or high performance. Amsoil usually has to be ordered as well as Redline but I find it easier than going down to the store. Type F might not be the best fluid for you and I would definitely do the switches before the Type F. If the trans only acts up when cold I would be looking at a DexVI fluid and adjust shifting characteristics by adding a little Type F if needed. Even the stock DW-1 is not a bad idea if it's acting up when cold.

Honda won't recognize the switches as a fix and by the time they throw a code you're on transmission #3. In fact, I've only heard of one pressure switch code ever and it was on a 2G. The ECU has to have a way to check the switches. For example, it checks the coolant temp sensor and intake air temp sensors by comparing their readings when the car is dead cold when both should read the same temp. I'm sure there's some kind of logic based on other things that are going on inside the trans, it would be crude and ineffective. It would detect a short or an open in the switches or the circuit but the switches don't exactly break or stop working, they get out of calibration. They influence a lot of things such as line pressure, shift timing, pretty sure throttle closing on shifts, the timing of the 3rd to 1st gear shift when you go from park to drive, and torque converter clutch application. The transmission will suffer a mechanical failure caused by out of calibration switches long before there's a code usually.

If I were trying to engineer in a consistent MTTF and make sure it didn't last too long, the switches are the perfect way to do it. They can cause the burned up 3rd and 4th gear clutches along with the converter clutch. They are an input; they do not directly control any component. It's next to impossible to set a failure code for one and they don't just stop working, they begin tripping at the wrong pressure which would never be known unless you pull them out and pressure them up to see what pressure they trip at. For what it's worth someone on here did just that with his old ones and new ones and it's posted on here somewhere. Who would ever suspect a pressure switch when the torque converter goes out or 3rd gear burns up?

Majofo

Definitely change out all the switches. The 3x3 didn't cause the issue. The issue was already there, just masked by the old fluid. I'd change the switches.. let it settle in and then consider another drain and fill of D4 or DW-1.

Majofo

IHC, there was member here who did throw the 4th pressure switch code. They took it to Acura and they told them that the trans was shot and needed to be replaced.

They might have posted here. I can't remember how it went but I think I remember they replaced the switches having found this thread and issue resolved.

pwr2panda

Just an update for you guys, I had the switches and filter replaced this past monday along with a 1x3 and have been driving it since then. It feels just how it was before the whole trans issue, maybe a little worse from the wear and tear, but then again I'm not pushing it as much as I had been before.

The mechanic showed me my trans filter and it was torn up/broken at the seams, and it wasn't filtering anything, just bypassing it. I remember reading about another member mentioning something about the filter having issues with disintegration at the epoxy joints. I'm guessing mine was original and hadn't been replaced ever.

So def replace transmission switches and filters for 04-06 if you havent! How often do you think filters should get done? Every 50K mi?

I hate cars

I missed your post until now. I'll have to look it up and see if he's on here. I would like to read about it.
Glad it's working better. I believe it's considered a lifetime filter because there is no replacement interval that I know of. Of course I would never go a lifetime on it, if only for the reason you experienced.

I removed mine completely when I installed the Magnefine filter on one of the cooler lines.

tones160

Does anyone know a reputable merchanic who may be able to change switches for me in NYC/NJ at a reasonable cost? My 08 Base A/T is at 57k.

Nick216

^ diy, its easy.

viking00

iTrader: (2)

It really isn't difficult at all. Just a tight space to work in but extremely straightforward and all the directions are right here in front of you. Just follow them.

I hate cars

I just did my 3rd set and didn't take the wheel off or jack up the car. I probably couldn't have done it like that the first or second time but now that I know exactly where they are, they've become a 5 minute job at most.

doggydog

If they set off a check engine light because they're way out of parameter such as an open or a short, would bad pressure switches prevent the transmission from engaging the gears? In other words, I turn on my car and step on the brake pedal, shift gears from P to L and no clicking sound, nothing.

doggydog

I Hate cars......

doggydog

Well $2700 for a rebuild FML.

iHeartmyHonda

I will bookmarking this page. I feel preventative maintenance is the key to long running cars. I will be replacing mine next weekend just for safe measures. The gears seem to switch fine but since these are not very expensive to replace and I have access to a lift it makes perfect sense to change them out. No service record is shown for these in my booklet either. better be safe than sorry right? :P

doggydog

Safe than sorry, yes. I changed the trans oil with 3x3 every 3rd or 5th engine oil change. Never drove her hard , never saw this thread so did not swap out the 3 and 4 pressure switch and at 164,000 my tranny just gave up.

dcmodels

A recent issue of Consumer Reports, on new car models and maintaining them, made an interesting statement. Paraphrasing - new car transmissions are good for 150K miles, and maintenance should be either change the ATF every 30K miles, or never change it.

I hope that my own RDX trans lasts more than 150K miles, so I am using RedLine D4/ racing mixed 1:1, plus I will soon be changing the pressure switches (3) at 50K miles.

flexer

Where are you guys getting the best deal on the pressure switches? Got any links for me?

DC2Teg97

www.acuraoemparts.com
www.hondapartsunlimited.com
www.acurapartswarehouse.com

all these you can get them for around the same price, give or take

I hate cars

Definitely not the switches. They may have caused excessive wear that eventually resulted in a failure but replacing the switches now will do nothing. Judging from your other thread, if you're lucky you might have had a pump failure or other hardpart failure. There are ways to diagnose a pump problem if you feel like spending the time.

Scottwax

Interesting about not changing it. When I bought my 4AT '02 Maxima with 113k miles, it was obvious the ATF hadn't been changed in a long time, the fluid was completely black. No burnt odor, just filthy. Did a couple drain and fills right away, then once a month for another 3 months. After that, once a year. At 195k miles when a drunk ran a light and totaled it, still was shifting great. And those 4AT's weren't any better than Hondas (and the 5ATs in the 6th gen cars were pretty horrible), known 2-3 cold weather part throttle upshift flare. Only real fix was the TransGo shift kit since it was a valve body issue.

Not sure there is any real difference between a 7th gen Accord/3rd gen TL automatic but so far so good on mine. Original owner had it serviced regularly and I've done 3 x 3 to get rid of as much of the Z1 ATF as possible and replace it with DW1. Nearly 153k miles now.

BTW, has anyone noticed when you reset the ECU, your transmission shifts more firmly? And not in a bad way (as in harsh), just a nice, positive feel.

Timthetoolman

What issue what this in?

dcmodels

Well, I really don't know - I visit the library once a month and just read a few magazines - I think it was one of the speciality issues on buying a new car, that is, all of the new cars, tips for negotiating a buying price, suggested maintenance, etc. The comment was in a section on how to maintain your car to last a long time. Issue was from the past couple of months I think - sorry cannot be more specific.

Acura-OC

If you have online subscription it is under
How to maintain your new car

Simple tasks that can make your car last longer

Last updated: March 2014

This is what it says: "
Change the automatic-transmission fluid

Many models require that you replace the fluid and filter every 36,000 miles—sooner if the normally pink fluid takes on a brownish tint. With some cars the fluid and, if applicable, the filter can go 100,000 miles or more. With other late models, the transmission fluid never needs to be changed. Check your owner’s manual for this information."


This is from beginning of article" ....reliability has improved significantly. The result is that most late-model cars and trucks should be able to go 200,000 miles with regular upkeep."

I hate cars

There is no such thing as a lifetime fill. I wouldn't do maintenence based on Consumer Reports recommendations, they have been made fun of a lot based on their automotive knowledge.

Lifetime fills use nothing special, BMW was exposed to be using a regular non syn DEXIII fluid in their lifetime fills. They know the car will make it out of the warranty period without changing the fluid so why would they care what happens after that. Meanwhile the fluid is breaking down and you're getting more and more contaminates.

To say to change the fluid based on it not being red and to say some never need to be changed just shows they're out of touch.

Timthetoolman

The Online Consumer Reports is free through some libraries.

I have owned a wide range of vehicles and my experience is that 3G TL needs more frequent changes than most cars and some manufacture's designs (my wild guess) would fail before old fluid would cause a failure. Obviously it is not a smart thing to go beyond manufactures recommendation, though.

One of my many cars is a 2000 Maxima and at 160k the original fluid looks (nice pink/red) and smells good. Nissan says to change if fluid has burned odor or contaminates can be seen. I will be changing it this summer and really should have changed it sooner and do not recommend this on any car.

I know that non pink does not necessarily mean the fluid is bad...My 2002 Accord V6 fluid always looks and smells good at recommended (normal duty) change intervals. Honda also recommends for this model a 1x3 and not a 3x3 to for less clutch wear because of "clutch break in".

Understanding what might be the right maintenance for each car makes sense.

Timthetoolman

[QUOTE=Timthetoolman;14972238]

One of my many cars is a 2000 Maxima and at 160k the original fluid looks (nice pink/red) and smells good. QUOTE]

My statement is not likely correct. I believe that I forgot to add the fluid change to my tracking spreadsheet that I did about 40-50k ago. My apologies.

Mkarl

FYI - A few years back I measured the difference between Old and New pressure switches and posted here. I now have some updated info on how critical these switches are and info on "yet another" design flaw to help explain why 3rd gear clutch packs fail.

Here is a link to the updated info.

3rd clutch pack failure and pressure switch update.

flexer

You seem to know more about transmissions than anyone. If the clutches slip and wear, I thought it would be good to raise the overall line pressure, but from reading your website it looks like raising line pressure would increase wear. Am I reading it right?

I hate cars

Great info!

It pretty much hits on all of the points I've made over the years on here. Now you can believe some of it since it's on a website and searchable with google.

cam_2

This is good stuff. Wondering where you got the pressure switch specs in posts 537 and 557, because I didn't see them in the service manual. Thanks.

Mkarl

Hi, I most likely read, spend to much time hunting down verified publications and forever hounding transmissions rebuilders until I get an answer.

From everything I have read and actual test data I have seen - line pressure is not the problem. Its has also been suggested that when Honda increased the size of one of the pistons for the 3rd clutch in 2004, they may have made the flaw in shift logic for a 4-2 down shift even worse.

We know about aggressive wear in the 3rd clutch pack when cold and under wide throttle downshifts. We know that cold fluid can accelerate clutch wear, and this is not just a Honda thing, but cold shift mapping holds off shifting into 5th until much higher speeds, getting on the throttle when cold at suburban speeds would almost guarantee a 4-2 down shift and this defect, I would think, would be magnified. Add a 3rd gear pressure switch out of tolerance and it's no wonder they fail.


cam_2 That info has been published before and is available, but you are right, it's not in the manual. Also of note is the report that some rebuilders have, in the past, used the same switch for both 3rd and 4th - apparently one was in short supply, apparently they had problems. There are 3 or 4 different switches that vary about 3 PSI between each. Honda accredited trans guys say even 3 PSI difference is bad for clutch timing and wear.

I hate cars As always, admire the work you have put into the forums and this transmission. I think your efforts with racing fluid is one of the few ways to get these hydraulic circuits to bleed down faster and reduce drag through the clutches.

Timthetoolman

What is the largest driving factor with the pressure switches loosing calibration: temperature and time at temperature?

How often should the sensors be changed?

Would monitoring transmission temperature give some indication that the clutch is slipping too much and changes should be made soon to reduce damage--assuming that all steps to minimize problems have already been taken?

Would the transmission life increase, on average, by adding thermal bypass cooler or thermal by pass valve (with added cooler) like Tru-Cool Thermal Bypass when temperatures could be as low as -20F (extreme low for short times of the year)?

I know that I am asking a lot but even knowledge speculation is appreciated!

Scottwax

Bookmarked, thanks!

Mkarl

The Switches are mechanical devices, there is a picture of them cut open on my site. They are affected by heat, age and the number of operations, just as most mechanical devices and they will age, no doubt about it. I likely replace every 5 years or 60K miles, I guess we all need to take more notice of that 2nd to 3rd shift under light throttle when cold, seems to start showing as a slightly extended feel to the shift under those conditions but who really knows.

Transmission cooler is really about driving conditions and local temperature, it's hard to say, sorry for being a bit vague with that answer.

Best way to monitor slip and TC is with an aftermarket Honda OBD interface as I believe that this can display a value of slip as well as input and output shaft RPM and of course TC lock-unlock commands.

I've been looking at the TCU to TC lockup command and IO slip but on a non Honda OBD scanner. I'll be trying the Honda unit in the next few weeks.

If bulk transmission temps start to rise abnormally then it may be to late to stop a problem, so IMHO monitoring the inbuilt temperature sensor would not help much for such a condition. I am currently tracking that sensor and the coolant temperature over time to test the effectiveness of the cooler and the ability to get quickly reach correct trans operating temperature.

Mkarl

I'm going to revise my first answer: As the transmission ages, pressure and design problems can start to kill the torque convertor.

Apart from the traditional heavy load and hill climbing conditions, transmission fluid temperatures also really start rising in slow or stop start traffic. With age and due to pressure leaks and design, flow to the TC is on the edge of being compromised, especially when stationary and in gear (D, R) and fluid like Z1 is not helpful. Oil viscosity is also an issue, in higher temps an overheated converter is more likely and high-quality synthetic oil will be helpful. At idle below 1200 RPM oil flow can almost shut off to the cooler circuit. This is reported to be one of the main reason for the numerous problems with TC overheating.

In very cold climates a cooler may not be much help but in warmer temps I would lean towards a cooler. However this brings us up against yet another design flaw. Honda uses a three-path TC flow circuit that incorporates a converter bypass valve, as a result it is sensitive to outside variables such as restricted coolers and cross leaks. Add to this an undersized pump and a restriction in the cooler circuit will cause the TC check valve to open and this will reduces apply pressure. Too much restriction and the check valve may position some valves in a partially blocked position. Without internal modifications the TC will overheat.

So if you use a cooler, use a low restriction unit and be careful with routing the lines, no tight bends, high quality hose and quality cooler. Whether you add a cooler or not, here is yet another reason to replace that filter and keep the cooler path as unrestricted as possible.

Apology for ramble, hope this does not confuse the issue.

Timthetoolman

Do you know if the 2004 stock filter filters oil before especially sensitive to contamination components better than an aftermarket filter in the cooler outlet line? The thought here is when removing stock filter to reduce pressure drop while adding external filter to improve filtering, will more good than harm be done?

Also, is there any benefit to monitoring the fluid temperature line coming out of transmission? Temperature changes will be seen much sooner than bulk temperatures.

It will be very interesting to see results from transmission slip testing!

Mkarl

Although the OE filter works fine if replaced every few years, I wanted to trap metallic particles (black paste) before they coat the filter, thereby decreasing flow over time. Most people are aware of the Magnefine filter and I added one a few years back (also did the Power steering).

Before I became aware of the sensitivity in the cooler circuit I made the decision to remove the existing filter from the housing (shock horror to some at the time) and I'm glad I did so. I was informed at the time that the existing heat exchanger was quite free flowing and on that basis I left it in line with a BIG plate filter, more for volume flow than anything else. At the time I didn't want to compromise trans fluid warm up.

I intend building a simple calibrated, low cost, Hi impedance module to allow a connection across the existing trans temperature sensor and have a small display for trans temps. Saves having OBD for this. I'll post details if anyone else wants to knock one up.

Yes I agree you should be able to see a TC starting to overheat as the outlet is fed from the TC. I'm toying with the idea of fitting a flow pickup to get a look at actual flow rates in worst case scenarios. I'd like to find a way to "TRY" and foresee impending troubles and get some real data for future testing.

As far as TC slip goes, again it should also be a simple matter to read the two speed sensors and combine it with the lock command to make a simple stand alone monitor that has absolutely no delay from OBD polling and is always connected and ready to go.

Some will think it's overboard or I'm paranoid about the trans, I actually am not (gave up on that years ago). My trans is shifting perfectly and I'm not going to let what may never happen spoil my ownership of this Honda.

I'm more interested in getting real data, it's easy for me to do so and gives more insight into the vehicle and of course the trans.