Hi Everyone,

I've been reading a lot on 3G TL transmission issues lately and am wondering if the 4G's tranny has similar problems.

For example, many 3G owners are recommending a periodic replacement of the 3rd/4th gear pressure switches. Looking at the 4G sensor diagram, it seems that our trannies also have a couple of oil pressure switches.

Perhaps, those of us with higher mileage should be looking into replacing them? Any expert opinion out there?


here is the diagram. I am referring to switches #12 and #13:
http://estore.honda.com/acura/images.../TK44A0710.png

 

I think the entire design of the automatic transmission is different between the 3G and the 4G, on all trims. Try matching the part numbers one-to-one for those actuators and see if they are the same?

The secret to transmission longevity is to change the oil often. The maintenance minder is ok to follow, but it doesn't account for the fact that these J engines suffer from heat soaking all over. So, changing the oil that has gone through a lot of hot-cold-hot-cold cycles and has lost some of its properties is a good thing. I do mine every other engine oil change. Then there is the torque converter issue that keeps coming and going... oh well. I am very tempted to change to a racing oil, like Red Line that has higher temperature tolerances, and a larger cooler but also too scared to do that...

 

I am like you. I actually purchased on oil cooler and then cancelled the order few hours later lol.

 

Looking back at the very first 5AT from Acura, as using in the 2G TL's and CL's.

Many 2G TL/CL owners reported transmission failure, soon after performed tranny oil changes.

Frequent transmission oil change was what killed the transmission, because the fresh oil dislodged all the loose clutch particles and smudges, and eventually clotted the tranny oil filter.

 

Speculation, your Honour!

 

π©^
If this was true those of us who do change our tranny fluid frequently would be dropping trannys ever 30k. A proper 4x3 every 20k or a flush with a [I]real[I] particulate filtering tranny machine will add years to the life of your drivetrain. In fact, while you're under there you might as well do the rear diff and transfer case. Perhaps they neglected to change the filter?

 

So I decided to go ahead with the replacement of the pressure switches. I took some pictures for anyone else interested in doing this work.

The 4G TL has 3 AT pressure switches (compared to the 3G TL which only has 2 switches). Having done both generations of TLs, I can say that the replacement of the 4G TL switches is just slightly harder. It took me about 1.5 hours to replace all three as I had to remove a few things to get to them.

So here is a diagram of the location of the switches. The 2nd and 4th clutch switches are part #12 in the diagram. The 3rd clutch switch is #13. #17 are the crush washers required for each switch (one for each switch for a total of 3):



2nd Clutch Pressure Switch:

The 2nd clutch switch is located in the back of the transmission and is accessible from the top. There is no need to remove anything to get to it. However, it’s in a tight spot so you might need to use a socket with an adaptor like this:



View from the top:



Closeup:



2nd Clutch replacement procedure from the manual:





4th Clutch Pressure Switch:

This one is located on the side of the transmission (driver’s side) and is probably the most difficult to get to. You need to remove the battery and air intake housing to get to it. I also had to remove the tranny cable bracket sitting right next to the switch as it was in the way.




Remove the cable bracket:



Closeup:



Replacement procedure:




3rd Clutch Pressure Switch:

(Sorry, I don’t have any pictures for this one. My hands were all messy with ATF and oil and I had nobody to help me with the camera.) This switch is accessible from the bottom of the car. You need to SAFELY lift the car on jack stands. Think safety because you will be crawling under the vehicle! Once the car is in the air, remove the splash guard. You will then gain access to the switch. Remove the driver side front tire and use a socket with a long extension and an adaptor (same tool as in the picture above) to get to the switch.

Replacement procedure:


While you are down there, you might as well do a 1x1 ATF change.

My driving impression after replacing these switches: The AT shifts great. There is no hesitation between shifts. Shifts are also smooth and quick. I can’t say there was a significant improvement but I feel a slight difference in shifting. Again, I did all this to prevent AT premature failure rather than to improve performance.

 

And here are the part numbers:

 

This is excellent information. I'm happy to see more technical threads (beyond cosmetic changes) here in acurazine. Could someone explain to me what happens when an AT oil pressure switch begins to fail? What should I look out for?

Thanks

 

Kakeyoro, if any of the pressure switches begins to fail you will definitely experience hesitation between shifts and hard shifts. If you have driven a long time with a failing pressure switch, you may have destroyed some parts of your transmission (like the clutches).

Now, having said that, it is unlikely that any of our 4G TLs will already have pressure switch issues. The reason I decided to spend about a $100 and replace all three switches is because of my experience with the 3G TL (I also own one of them).

With the 3G TL it is considered good practice to replace these switches every 60k or so in order to avoid costly transmission issues. There are many threads on the subject that go in depth on why these switches are weak links in the tranny.

Here is one of the main threads:
https://acurazine.com/forums/3g-tl-2004-2008-93/very-interesting-conversation-my-transmission-builder-tl-721508/

To give you a quick summary, these pressure switches have a tiny membrane inside. After a while, this membrane begins to deteriorate and the switch no longer detects the oil pressure accurately. As a result, it will send wrong data to the tranny controller which will in turn use this data to incorrectly shift gears. Some people are even saying that the controller might engage two gears simultaneously which could create a HUGE problem.

Since my 4G TL is now nearing 80k, I decided to play it safe and replace these switches and post this DYI for anyone else who is paranoid like me

 

hmmm, my wife has a 4th gen and I have the 3rd gen....I about to change the pressure switches on mine again and was thinking should I do the same for hers, but I haven't seen many people talking about the 4th gen....at least not here...I'm wondering if I should go ahead and do it....she's at 90k...

 

These switches are pretty much identical to the switches used in the 3G trannys. I think all of them are manufactured by Texas Instruments. So there is no reason to think that the switches in the 4G are immune to failure. I'd just go ahead and change them periodically.

 

Yes, the originals were from TI - the current updated part number switches are Made in CHINA, no specified manuf. I wonder if they will be any better (or worse) than the original switches?

 

As the 'controller' (PCM or Powertrain Control Module) has all kinds of fail-safe controls, the HUGE problem described above is likely to be a hydraulic or mechanical issue.

 

Along with the pressure switches, I also recommend getting an inline cooler and magnafine filter. I had a 01 Accord V6 and my transmission was replaced at 30k, afterwards I installed a B&M cooler and a magnafine inline filter, I did a 3x1 and changed out the magnafine filter every 12k miles and my transmission was fine up until it was totaled at 145k. It was my first car and I was young so I drove it hard.. redlining it often and neutral dropping it all the time and the transmission was still fine. I recently ran an autocheck on it and it's still on the road with 180k miles.

 

Good suggestions. I have a magnafine filter on my 3G. I also periodically replace the OEM transmission filter which is easily accessible.

The 4G's filter is inside the casing so you can't replace it but you could easily add a magnafine. I am pretty sure the 4G comes with a cooler (at least the awd version).

 

I have a 6MT now, I'm not sure if I could add an inline filter or if it's even necessary