Perform Do-It-Yourself auto maintenance at your own risk. You can kill or injure someone or damage the car. Raise an auto only on a level, concrete floor. Do not go under any auto unless you are completely certain that it is secure. You and only you, are responsible for your work and safety.

There are many ways to raise an auto for service. Jacks, ramps, scissor lifts and stands, etc. All auto lifts share a few traits, though: they are cunning -- they hate you -- and they want you dead! The RDX weighs 3950 pounds. If it falls on you, that's 3850 more than it needs to crush your skull and emboss the phrase "engine oil" in mirror image on your forehead . DO NOT go under an auto unless you are completely certain it is secure!

Front and rear, left and right is ALWAYS related to the car itself, NOT how you are facing it:
LEFT is always the DRIVER side.
RIGHT is always the PASSENGER side.

Text relates to the picture below the text.

Parts and tools needed:

1. One case (12 qts) Honda ATF-Z1.
2. Transmission drain plug seal washer, part # 90471-PX4-000.
3. Measuring funnel connected to 9 mm OD nylon hose, for filling through the dipstick.
4. A 10 mm wrench.
5. A 3/8" drive ratchet and short extension.
6. Small torque wrench (preferred).
7. Drain pan (minimum 4 liters) and old measuring container for measuring the drained fluid.
8. Eye protection, face protection, gloves and protective clothes.
9. Newspapers, rags, etc.

To service the RDX transmission, ensure that the engine is cool or only slightly warm. Put on your protective gear. Transmission fluid is hazardous to humans and will damage the car's paint.

Disconnect the negative battery cable (10mm). This safety precaution always applies to auto maintenance:



Look up at the bottom of the engine and you will see that the engine oil drain and transmission fluid drain are facing one another. Getting these two confused has made quickie-oil-change places famous for draining the tranny and then over-filling the engine with 5 additional quarts -- then ten miles down the road, the tranny is smoking and the engine is puking oil!

We should all try to avoid that sort of scenario and Honda has helpfully given us a few clues:



On the right is the engine oil drain, which takes a 17 mm hex wrench:



For our benefit, it is marked:



On the left is the transmission drain, which takes a 3/8" drive:



Use the 3/8" drive and extension to remove the drain bolt:



Drain the fluid and measure it. Honda says to expect 3.3 L (3.5 qts). It is difficult to determine the transmission fluid level, so it's important to replace exactly the amount drained:



While it's draining, examine the drain bolt. It has a magnet for capturing metal particles in the fluid. There should be some sludge on the magnet. This is normal:



Clean the drain bolt:



Here are the seal washers. On the left is the transmission fill seal -- I don't use this one. On the right is the transmission drain seal. Don't use this one yet. There are 3 tranny drain/fills. The new seal will go on after the last drain:



When the first drain is complete, wipe up the residual fluid and re-install the drain bolt with the old seal and snug it down. Don't over-torque the old seal -- it's only temporary.

Place the hood in the service position:



The transmission fill port is located on top of the tranny beneath the brake reservior. In this picture it is reflecting a flashlight so it appears close, but it's 35 cm (about 14") down there. It's nearly impossible to reach without removing the airbox and then a funnel or tube must be snaked down between the wires and components. Alternatively, filling through the dip-stick is slow, but so is removing and installing the airbox 3 times for each fill. I do not remove this plug , but if you want to use it, the seal washer is part # 90441-PK4-000.



This is a measuring funnel with nylon hose from WalMart. It has an on/off valve and cost about $3. I added a 9 mm OD nylon hose connected by a brass barb. The funnel hangs from the hood latch with some old house wire and the 9 mm hose fits perfectly into the dipstick tube -- won't shake loose and doesn't leak:



Remove the transmission dip-stick. Wipe it clean and place it aside:



Hang the funnel from the hoodlatch securely with house wire. Insert the 9 mm hose into the dip-stick tube about 25 mm. Close the funnel valve and add some ATF-Z1. Start with small amounts --be careful not to add so much that the funnel tips. Put the lid on the funnel to protect the fluid. It's a good precaution to cover the engine with newspaper as well.

When everything is secure, open the valve and start the flow:



Check for a good seal at the dip-stick tube:



Check for a good seal at the hose connection:



Add exactly the amount of new ATF-Z1 that was measured during the drain. Use the measuring funnel and the sight gauge on the bottles of ATF. Three/plus quarts should take about 15 minutes. Insert the dip-stick. Reconnect the negative battery cable and police the area before moving the car.

Drive the car around the neighborhood. Make sure it operates in all 5 gears and reverse, to circulate and mix the fluid, but don't get it hot. Five minutes will do.

Do the battery negative cable safety procedure. Drain the fluid again. Reuse the old drain seal washer. Fill and drive again.

On the 3rd drain/fill use the new drain seal washer and torque it enough to crush it slightly (49 N-m, 36 ft-lb).

To determine the actual amount in the tranny, use Honda's procedure in the owner's manual: Park the RDX on level ground (air conditioning off) and allow the engine to warm up to operating temperature. The radiator fans should come on once. Turn the engine off. Do not allow it to warm up beyond one fan operation. Check the transmission dip-stick within 60 to 90 seconds after turning the engine off. The level must be between the upper and lower marks. If needed, add or drain small amounts to adjust.

I did this procedure very carefully. Initially I had to extract 500 ml (using a fluid extractor), then added 100 ml back in. I got the level perfectly at the lower edge of the top hole using the Honda procedure.

Then I drove the car to full operating temperature and took readings. Immediately after shutdown it was on the T (in HOT). Over the next 90 seconds it climbed to the top hole. Five minutes later it climbed to 1 mm above the top hole. One hour later it was 2 mm above top hole. The next morning at full cold it had returned to the top hole where I had set it using Honda's procedure.

The point of all this is that it gives a pretty good reading after a hot drive if you check it in the 60-90 second window. It also shows the same level as the Honda procedure when checked full cold. I've been checkng it full cold for 4 years now and always get the same reading as the Honda procedure:



I first did a flush/replacement at 40k miles. I did this second one at another 35k miles. The improvement in shift smoothness and acceleration is marked and immediate, with fresh ATF. I plan to do this now every 30k miles.

A great place to dispose of your tranny fluid and engine oil is your local independant auto shop. They heat the service bays with waste oil and really appreciate it. You'll also make a friend with a shop

 

Great post!!! I did the same DIY, but without all the details like yours.

 

Thanks.

I forgot to mention; wipe the tranny dry after the 3rd fill, so you can do a leak check after driving it.

 

Yes, Nice job. It's great to see someone who genuinely contributes reliably accurate information with photographic evidence (the best I've seen here on AZ). Because I’m a guy, after all, I’m visual.

 

Subscribed and thanks again , Jock!

 

awesome. thank you

 

Nice post, it will come in handy next weekend!

J

 

737 Jock:

What a great write up! I performed the ATF drain and refill last night. I followed your method and went through to dipstick tube to fill the tranny. Worked great.

I didn't have a small tube to stick into the dipstick tube but I did have a large enough one that securely attached around the tube. I was able to dump 3 an 3/4 of ATF fast down the dipstick tube.

Checked the fluid per Honda's guide and it is right at the top hole. Shifting is buttery smooth.

Thanks for all your write up on this board. I've been using them for all my DIY's.

 

I'm stupid but why do you have to drain and refill so many time? It's not like an oil change?(drain and fill and be done).

 

You are right. I just assumed that was understood.

The transmission holds 7.8 L, but less than half of that can be drained -- the remainder stays in the torque converter. So one drain/fill replaces less than half the fluid. The only way to flush the torque converter is with a power flush machine, which Honda warns against using.

Otherwise, 3 drain/fills are reasonably effective to get a full flush of the old fluid.

 

Thanks for this DIY.

I just changed mine today through the fill plug. It's clearly marked with "ATF" on the plug and is not so hard to reach if you have an aftermarket intake such as the K&N Typhoon.

 

Great DIY, thanks for sharing.

 

Here is how dealer does
TRANSMISSION FLUID FLUSH PROCEDURE.
2007 ACURA RDX 2.3L L4 DOHC i-VTEC (K23A1) TRANSMISSION
Description:
Acura Approved Transmission Flush Procedure.
Requires 12 quarts of Honda ATF-Z1 Fluid.
Techs in the field advise using only Honda ATF-Z1 in Honda and Acura transmissions. Apparently, other fluids will cause harsher shifting characteristics noticeable to the customer.

Procedure:
1. Set the parking brake, and raise the vehicle on a lift.
2. Drain the trans, and refill it with Acura Precision Crafted ATF-Z1.
3. Start the engine, shift into Drive, and release the parking brake.
4. Push down on the accelerator pedal to raise the vehicle speed to 2,500 rpm.
If the trans shifts past 2nd gear, go to step 5.
If the trans won' t shift past 2nd gear, keep the engine speed at 2,500 rpm and shift from Drive to Neutral and back to Drive. Then go to step 5.
5. Make sure that the trans shifts through all the forward gears and goes into torque converter lockup.
6. Let off the accelerator pedal, and press the brake pedal to drop the vehicle speed to zero. Shift into Reverse and then into Neutral.
7. Shift into Drive, and repeat steps 4 thru 6 four more times.
8. Set the parking brake, and repeat steps 2 thru 6 two more times.
9. Drain the trans, and reinstall the drain plug with a new sealing washer.
10. Refill the A/T with ATF-Z1.

 

Acura and Honda ATF-Z1 transmission fluid will be replaced with Acura Honda DW1.
I just got 5 cases for my shop today.
55 cents higher then Z1 fluid.

 

Thank you for your post. My old trans oil was pretty dark! Hopefully I changed it just in time, before any internal damage occurred.

 

To make a quick check of your trans fluid, compare it to a fresh bottle of ATF-Z1. Put drops of each side-by-side on a clean, white paper towel. Pull the dipstick and let it drip onto the paper towel, beside a few drops of fresh fluid.

The drops should spread out quickly and evenly. Less spreading is more contaminated.

It should have a red tint to it. Cherry red is good. The more it tends toward brown, the more contaminated it is. (Sorry, I haven't seen or tried the new DW-1 yet. Don't know what color it is.)

Compare the odor to the fresh fluid. It should be similar. A burned smell is call for immediate replacement.

 

How about a trans fluid flush at the dealer done with the machine that connects to the hoses at the cooler and pushes all the fluid out while refilling at the same time? that technique supposedly removes all the old fluid and cleans the inside of the trans real good.
Great post, but I am mentioning this because I recently saw it on Motoweek tv and it was a sweet set up, good way to clean the inside of the trans and get all the fluid out, very useful if the goal is to get rid of the atf-z1 and replace it with dw-1.
What do you guys think about that method, and how do they connect the hoses, is it done via the trans cooler lines in front? And how much does it cost?

 

See post #10.

 

Why do they warn against it?, does it damage stuff inside?
On Motorweek tv, they said it was the only way to remove accumulated crud from inside the converter and that it would triple the life of the trans.

 

I just did mine today in the garage. Pretty simple.

I removed the airbox and used the trans fill. I started the car and went through all the shifts with the car running and no airbox 3 times. With as much rain as we have had and only running it for a few minutes there is no chance it will hurt the engine.

My fluid was very dirty, and the plug had quite a bit of shavings on it. After driving it cleaned out it shifts much better.

think I paid about $70 for a whlod case of fluid.

So next week its the diff fluid and brake fluid.

 

Consider the sponsorship the tv program.

Honda recommends against system flushing:

 

A January 2008 follow-up bulletin; "The Latest Word on AT Flushing", details 3X drain/refills and running the car on a lift as littleblazer listed in post# 13.

 

Did you use DW1 or Z1?

 

Thanks for the info.
What about people reporting DW1 not shifting as well as with Z1, any info on that?
As soon as I get an RDX, I'll do the 3x trans drain/refill, but I don't want to buy a case of DW1 if it ends up making it worse and then re-do it with Z1 (which is available on E-bay), thoughts/experiences? Thanks!

 

Come on! nobody's running DW1?

 

Thanks OP for the write up. Completed this last weekend. Reverse shifts are a lot smoother now.

 

My shifts were a little harsh before. Once I flushed with DW1 they feel much better. I even noticed there is less delay in shifting with the paddles. /FWIW

 

Just did the 3x flush with new recommended fluid, removed air box for filling used same funnel OP used, got it from Walmart.

Piece of cake!

 

My delay for the 1-2 shift is about 1/2 to one second, which allows the rpms to climb about 500 rpm before the shift actually occurs, at about 1/2 throttle. The other shifts (2-3, etc) have slightly less delay.

Wondering how much delay you experience. And if any delay is dependent upon how much throttle is used, or at what rpm the shift is initiated? Thanks for any response.

 

Did this this shft delay occur after using DW-1?

If so, could you provide some details; how much DW-1? how long after? is it getting worse? etc.

I haven't switched to DW-1 yet. Reviews on the 'net vary widely between "better and smoother" and "worse and harsher".

 

I have the new stuff in there haven't driven it yet , wifey does and she wouldn't know difference. I will be taking a trip this Saturday with family in RDX and will post anything I may notice different .

 

OK, here is a sort of answer to your question, at the risk of hi-jacking this thread, which is not my intention. I actually posted a new thread asking about shift delays. Only a few people responded, and the general response seemed to be that some shift delay is normal, for those responding.

LINK: https://acurazine.com/forums/showthread.php?t=840824

MY EXPERIENCE with SHIFT DELAY:
Regardless of ATF used, the shift delay has not changed. Nor has the delay changed with vehicle age.

When using the paddle shifters, the 1-2 shift has a delay of almost one second. That allows the RPMs to increase by about 500rpm between the moment I initiate a shift with the paddles, and the start of the shift. The shift itself is quick, the delay is before the shift begins. The shift delay for the 2-3 shift is less. And with heavy throttle by the time I hit 3-gear I am doing 80mph or more, so I have never held heavy throttle for the 3-4 shift. I just do not want to try a 100mph shift to 4th.

This shift-delay is independent of the throttle position. That is, whether light or heavy (full) throttle is used, the delay seems the same to me. But perhaps not quite, as the RPM increase of 500rpms also seems the same, before the shift is begun after initiation with the paddle. I understand any confusion from this statement, because at heavy throttle, engine speed increases much faster. My own perceptions seem to slow when I go faster, so perhaps the actual delay time at heavy throttle is less than at part throttle.

During vehicle break-in, during the first 500 miles, I used the paddle shifters a great deal. But only to control (limit) the max RPMs, and always at very light throttle. So it seemed to me that a small delay at light throttle was ‘normal’. Only later when I used heavy throttle during a sift did it seem that a delay should not be so long.

MY LIMITED EXPERIENCE with DW-1 ATF:
You asked about DW-1. My experience with that ATF is limited, but I noticed no particular difference from Z1. However, note that the DW-1 was never 100% (or even close), nor mixed with Z1.

MY EXPERIENCE with non-HONDA ATF:
The only basic difference I have noticed, regardless of ATF mix, is that more than 50% RedLine Racing will cause some shift problems after about 3K miles, but boy, is the shifting quick and decisive (until 3K miles). Also, the more Racing ATF is used, the less crap I see on the drain plug, but there is always some there. The RDX trans just seems to generate a lot of swarf. And with mostly RedLine D4, I am not certain there is any significant shifting difference from Z1.

I am currently running a 50% RedLine Racing and 50% RedLine D4 mix. At very light throttle, just enough to cause a shift, the 1-2 shift is noticeable (but not firm), until the car warms up, even if it is 100 degrees outside. The more throttle is used, the less noticeable is the shift. For me, the shifts at part throttle with Racing are ‘quick’ but not firm. Of course, I always found shifts with 100% Z1 to be somewhat ‘soft’ almost to the point of too-slow. And I normally drive a GM vehicle with a “do-not-let-the-driver-we-are-shifting” transmission.

I think that the reason the following mixes work at all, is because of the DBW (drive by wire), which closes the throttle for a few milliseconds between shifts. I find the paddle shifters so ‘bad’ that I just do not use them. I do not think that my wife has ever used them. I am not the daily driver.

ATF MIXES I HAVE TRIED:
Remember that the transmission holds 8.2 quarts, according to the FSM. 0.2qts is only 6.4 ounces, so I have basically ignored that small amount in the following.

1) Until 17,620 miles only 100% Z1 ATF was used. My first drain-and-fill occurred at 07,875 miles.

2) At 17,620 to 17,926 miles the fill was altered to 87% RedLine Racing ATF and 13% Z1

3) At 21,260 miles the fill was 1/2 Honda DW-1 and 1/2 RedLine Racing = 50% racing

4) At 21,315 miles the fill was 6qts RedLine D4 + 1qt DW-1 + 1qt RedLine Racing = 12% racing

5) At 22,443 miles the fill was 5qts RedLine D4 + 1/2 qt DW-1 + 2.5qts RedLine Racing = 30% racing

6) At 27,050 miles the fill was 3.5qts RedLine D4 + 0.25qts DW-1 + 4.25qts RedLine Racing + 6.4 ounces mix of all of the above = 8.2qts = 52% racing

7) Current mileage is about 27,500 miles.
---EOF

 

Drove about 160 miles for the day this past Saturday noticed no difference with the new fluid , transmission has smooth shifts , no delays noticed .

 

To clarify, are you saying that you note no delay when using the paddle shifters? I only notice a delay when up-shifting with the paddle shifters, and not when in automatic mode. And the delay is not in the actual shift, but the time between 'requesting' a shift with the paddle, and the actual start of the shift.

 

Thanks for the info dcmodels and wifesRDX.

I still have a full case of Z1, so I'm going to add in DW1 gradually. The Honda bulletins authorize dealers to mix Z1 and DW1 in their bulk stock so it shouldn't be a problem.

 

I wasn't using the paddle shifters but will drive it today in manual mode and will advise.

I think I remember the delay you mention with the paddle shifters when I use to play with them , now just use auto mode when I drive it.

 

This is a very nice post. Thank you. I was curious why Acura said to only use their ATF? I have a Volvo S70 and i used Mobil 1 synthetic ATF. Is the Honda ATF synthetic?

 

any difference in the transmission service procedure on a front wheel drive RDX?

 

Yes, new Honda ATF - DW1 is synthetic

 

Thank you for replying to my message. I thought i would ask whether or not people on this forum knew whether or not its safe to buy acura motor oil or transmission oil,etc on amazon? I wanted to know if anyone has done it? Problems? I know everyone wouldnt want to get a substitute product with all the correct labeling and packaging then find out that the product wasnt really from acura?