dcmodels

My thoughts and opinions (JMOs) about my own 2009 RDX transmission oil change(s), which I have now done 5 times (about 4 quarts each time). Perhaps some may find the following ideas useful.


READING the TRANSMISSION OIL DIP STICK of the RDX:
I have concluded that the area between the two holes, the read-area, represents 8 ounces of fluid. The area between the FULL and ADD holes (marks), measures about 8mm, so each 1mm = 1 ounce of fluid.


HOW TO READ THE TRANSMISSION OIL LEVEL of the RDX:
You can read your Owner’s Manual for the official method of taking a reading of the oil level of the transmission. For my car, the HOT reading is always about 3 to 4mm above the COLD reading. So I adjust the COLD reading about mid-point between the Hi and LO marks on the dip-stick. My car was delivered from the Dealer with the COLD reading at the bottom mark on the dip-stick.

This difference between HOT and COLD readings, may differ from what others have posted, so perhaps I am doing something slightly different from them in taking a reading. The manual says to run the engine from cold, until the radiator fan runs once, but not twice. And to do this with the heater/ AC system turned off.

If the temperature is less than 80 F degrees, I have found that letting MY engine run at idle speed will NEVER cause the fan to run (I gave up after 38 minutes). It is necessary to hold MY engine speed at 2000 RPM until the fan runs. I do this ONLY after letting the engine reach ‘normal’ temp at idle, based on the MID gauge reading of 7 bars. That is normal temp for my car, and never varies, no matter how the car is driven, or what the air temp is.

For my car, it takes between 5 and 10 minutes for the fan to run, depending upon the outside air temp.

When the fan starts running, I allow the engine to return to idle speed. Then when the fan stops running, I wait 10 seconds, then turn off the engine. Then I take an oil level reading at 90 seconds, as near as possible. That is, I insert and pull the dip-stick just before 90 seconds after stopping the engine.

The above method produces the same reading (for me), whether the air temp is 40 or 90 degrees F.

WHY DO A COLD READING?
I find it time consuming and difficult to get a consistent ‘hot’ reading of the transmission oil level. If you know where the COLD reading is in relation to the required HOT level reading, then you can just use COLD readings to check the trans fluid level. Also, you can take as many COLD readings as you like – they will always be the same when taken in the same time period.

You only get one chance at a HOT reading, as any subsequent HOT readings will differ (and be wrong). With a HOT reading, the oil level keeps changing (increasing) the longer the engine has been stopped.

HOW TO TAKE AN ACCURATE COLD READING:
OK, you are thinking that a COLD read is just check the trans level when the engine is cold. No, that will not always work; and is probably why Acura states to check the oil level with the engine hot. For example, if you drain the transmission and then refill with the same amount of oil drained, the transmission will read some unknown level, until after the engine has been run through all of the gears.

To get an accurate COLD reading of the transmission oil level, the car must be driven until the engine is completely warm. And all of the gears (including reverse and park), must be selected at least twice, pausing in each selection about 3-5 seconds. Then park the car overnight. Before starting the car the next day, check the level. That is your valid COLD reading.

COLD READING after a DRAIN-AND-FILL:
Now, you do not want to be driving any distance with the wrong oil level. So after a drain and fill you must try to get very close to the correct oil level, before driving, and before checking for either a valid HOT or COLD reading. This can only be done if you have carefully measured the amount of oil that was drained, and refilled with that amount.

After refilling the transmission after a drain, start the engine and position the gear-selector through all of the gears a couple of times while the engine idles. Then stop the engine and wait 5 minutes, and take an oil level reading. Only then will you get a realistic read of the level. But this reading will not be completely accurate, only a close estimate. If the level looks good, I also drive around the block (literally), and park back in the garage. Then I wait 15 minutes or so while I clean up, then take another reading. If necessary top-up the oil.

Do this procedure with a cold engine, or at least after the engine has sat for a couple of hours (or while you were changing the oil). This is why it is so important to measure the amount of oil drained, and refill with that exact amount.

You can then take a COLD or HOT reading the next day, to verify that the level is accurate.


HOW MUCH OIL for a SINGLE DRAIN and FILL of the TRANSMISSION ?
The RDX manual (Owner’s and Factory Service both) indicate that 3.5 quarts is required to refill after draining the transmission by the drain plug.

Each time I have drained the transmission, just over 4 quarts drained, not 3.5 quarts. Perhaps this is because I drained the trans while hot, and let it drain for around 20 minutes while I cleaned up a bit, and got ready for the refill. I also make certain that the dip stick is either removed completely or loose. Careful, that draining oil can be really hot – I wear nitrile throwaway gloves.

I prefer to drain the transmission while hot, for the same reason as draining the engine while hot – the oil drains better, more completely, and more sludge is removed because it remains suspended in the oil.

Elsewhere on this forum, someone has kindly posted the procedure for doing 3 drain-and-fills, back-to-back, in order to replace most of the fluid in the transmission.


MEASURING FOR DRAIN-AND-FILL:
The amount of fluid which drains from the transmission does not seem consistent enough to know _exactly_ how much to re-fill.

So I try to catch every drop that drains from the trans, and then carefully measure it. I use a big drain pan and try not to spill or overflow. Then I measure all the drained fluid using a quart measuring container. I believe that the dip-stick is only 8 ounces between the FULL and ADD holes. So it is necessary to measure to the ounce, from those 3 or 4 quarts that you drained. That is the amount you need to put back into the transmission.


WHY DO A DRAIN AND FILL OF THE TRANSMISSION?
My Owner’s Manual says to replace the transmission fluid either (1) when the MID indicates, or (2) at 60K miles if you live in a mountainous area, tow, drive slowly (to work for instance), etc. Some say that this means a simple drain-and-fill. But to me this means REPLACE ALL OF THE FLUID. That is how I understand the manual which says “replace the transmission fluid”.

Anyway, I also believe (as an engineer) that most of the wear on the transmission gears occurs during initial break-in. If those metal wear particles are not removed early, they just hang around inside the transmission grinding away on the gears and clutches.

When I did my first 3 times drain-and-fill at 8K miles, the drain plug magnet was completely saturated, meaning it could not ‘hold’ or capture any more metal filings. I must assume that the internal “cannot-be-replaced” magnet and ‘filter’ are also saturated. Once the magnets are saturated, the magnetic particles will be attracted to the solenoids (basically electro-magnets). And there is basically no filtering of non-magnetic particles. Draining the oil is the only way to remove the non-metallic particles.

I did two more drains at 15K miles, and the drain plug magnet had heavy deposits on it. So at that time, I also installed a replaceable inline magnetic filter into the cooler lines. This inline filter is primarily to capture the non-metallic (clutch) wear particles. I will post a HOW TO on this later. I plan to replace this inline filter every 12K miles, along with a single drain-and-fill of the transmission.


REFILL THE TRANS USING THE DIP-STICK HOLE?
I have personally not found a good way to do this. Sometimes the hose connections slip loose from my funnel, because of the oil. Finding small tubing that is not too thick has been difficult. Filling is also very slow. If I find a way that really works for me, I will be certain to share.


TOP-UP THE TRANS USING THE DIP-STICK HOLE:
I insert a Turkey Baster, with the squeeze bulb removed, into the dip stick hole. Then I insert a small funnel into the top of the Turkey Baster. This is a simple and fast way to add a few ounces to top-up the transmission, if required, after a drain-and-fill. I would not try to add more than a few ounces, and certainly not 4 quarts, with this method. I give credit for this method to some (unremembered) person on this web site in the TL forum section.

The problem is that I have 4 basters (don’t ask), and only one of them fits into the dip stick hole. So you will need to measure and try to find one that works for you. Another possibility is that I found small cosmetics funnels at my local bakery type shop (Spoons ‘n Spice) that fit into the dip stick hole.


THAT PESKY TRANS OIL FILL BOLT:
I refill the transmission using the oil fill bolt, located on top of the transmission, just to the passenger side of and below the brake master cylinder. It’s a good 15 inches or so down there. I remove ONLY the turbo intercooler cover, and the 90 degree air box intake hose, then the bolt. This takes me less than 5 minutes. I can then dump 4 quarts of transmission fluid as fast as they will drain from the bottles.

First, find the bolt. Use a flashlight and look for a 17mm bolt head, with the letters “ATF” embossed on the head. The Owner’s Manual has a line drawing showing the location.

I admit that if your hand is much larger than average size, you may not be able to reach and remove this bolt, without removing the complete air box. But you can easily determine if you can reach the bolt, by removing a couple of parts, then loosening the bolt. If you can put your hand on the bolt and turn it and hold it with your hand, then this method can work for you. Otherwise, just re-torque the bolt and use another method to refill the transmission.


REMOVING THE TRANSMISSION OIL FILL BOLT:
The following is how I do it. It may seem long, but will take you longer to read than to do it:

Ř The day before draining the transmission, dump a bucket of water (2 gallons) on the transmission fill bolt. THE ENGINE MUST BE DEAD COLD. This will prevent any dirt from entering the fill hole when you remove the bolt. Driving the car (engine heat) will dry the area so you do not get any water in the hole either. Neither dirt nor water will be good for your transmission.

Ř If it looks really dirty down there, spray a little cleaner on the area, then clean with water. I do not recommend using the water hose, as you may get things wet which should not be wet. Remember, the vehicle fuse box is just to the driver side of the brake master cylinder. Getting a bit of water on it will not hurt – spraying it with a high pressure flow may cause problems. I use Simple Green cleaner, the one specifically for engines, which states that it is safe on aluminum. The regular stuff from the grocery mart is different.

Ř I have tried removing various parts to gain access to the fill bolt. The only thing that has worked for me is to remove the two items listed here below. Moving the Fuse/ Breaker Box to the left of the Brake Master Cylinder will not help, because the bracket to which it attaches cannot be moved.

Ř Remove the cover on the turbo intake cooler. Use a quarter ($0.25) to turn the four slotted ‘screw-heads’ 90 degrees. Jiggle the cover, to make certain the pins are loose. Lift the cover, and set aside.

Ř Remove the engine air intake hose between the air filter box, and the engine intake at the firewall. This hose has a 90 degree bend, and length of about 12 inches.

Ř There is a hose clamp on each end of the air intake hose. Look carefully, and you will see a yellow paint mark under the opening of one of the slots in the end of the clamp. On my vehicle, this mark is under the 4th slot from the end of the clamp. This will allow you to re-tighten the clamp to original spec, without over or under tightening. If the mark is no longer there, count the number of slots from the screw head, for reassembly. Note the count on paper for later reference. Or paint a mark at the end of the clamp onto the clamping part, using red finger nail polish.

Ř Remove the wire loom from the rubber slot in the air intake hose. Note the WHITE wrap around the loom where it fits into the slot.

Ř Remove the intake hose by first twisting the end on the filter box up by 90 degrees, then pull from the firewall connection. Cover the open ends of the air filter box and the intake at the engine firewall, with small CLEAN plastic bags.

Ř When replacing the intake hose, apply a very thin layer of SUPERLUBE grease on the inside of the hose ends. This will prevent the hoses from ‘welding’ to the plastic fittings. Do NOT use silicone dielectric grease. You would not use silicone sealer anywhere on an engine, unless it is stated that it is emissions safe. So do not use silicone grease on this intake tube. I buy Superlube from ACE Hardware in a small tube (maybe 4 ounces) for about $6. I really do not know what other grease would work, without damaging plastic/ rubber or melting.

Ř Look below the positive battery cable on the passenger-side back corner of the battery. There are two emission hoses just larger in diameter than the cable (which makes a 90 degree curve around the back side of the battery). Do NOT try to move the battery cable, or disconnect it from its clamp or the battery. You will not gain any useful space.

Ř The two emission hoses are located one above the other. There is a white plastic ‘C’ clamp holding the two hoses in place at the back corner of the battery. Reach down and push (horizontally toward the passenger side) the top hose out of the top half of the clamp. You can also push the lower hose out of the bottom half of the clamp, although I do not find this necessary. Do this by pulling up on the top of the C clamp with your left index finger, and pushing the hose with your thumb, out of the clamp.

Ř You now have just enough room to reach your left hand down and find the fill bolt on the top of the transmission. Verify that you can do this, before you use a wrench to loosen the bolt. If you are right handed (like me), you will want to use your right hand. Sorry, that just will not work.

Ř I use a 1/2 inch drive 17mm socket with 15 inch (or more) extension, and wobble adaptor on the socket, with a 14 inch long breaker bar. Make certain that the socket is square on the bolt head, because the extension will be slanted to miss the brake master cylinder at the top. There will be a loud ‘pop’ when the bolt breaks loose. This is normal, because the aluminum washer tends to gall and cold-weld to the trans case. You will need between 50-75 pounds of force to loosen the bolt.

Ř NOTE: if you drop the fill bolt or washer you are going to find it difficult to recover them. The bolt will probably fall through under the car, or you can use an extendable magnet to recover it. However, the washer is probably lost for good (its aluminum). So have a replacement washer (or two) in hand.

Ř I use a long narrow top funnel into the fill hole on the transmission top. With a bit of ‘jiggling’ it just fits under the brake master cylinder and into the hole. Then I use a wider topped short (or long) funnel into the lower one, and dump oil into the top funnel. Look as you fill the oil, to make certain that you do not overflow the lower funnel – bottle in one hand and hold a drop light with your other hand (to see). I do not like the funnels with the long flex hose, as I figure that the flexes in the hose will trap oil/ dirt, and be impossible to wash out. I wash my funnels after each use and store in a sealed plastic freezer bag for the next time.

Ř I do not replace the bolt sealing washer as it costs over $5 each. I put a drop of trans fluid on each side of the washer. Hold the washer on the bolt with the tip of your finger and ease the bolt into place. Start the bolt by hand. Do not even think of using a drive wrench to start the bolt – it will cross thread for certain. Screw the bolt all of the way back in by hand, to prevent yourself from cross-threading it. If the bolt does not start easily, pull it back out and start over.

Ř I use a 50 pound reading 3/8 inch drive torque wrench, with adaptor to 1/2 inch drive, and ratchet adaptor to ease rotational alignment of the wrench. I torque to 25 ft-lbs, not the 33 ft-lbs factory specification. With the lubed washer, I always get a smooth and reliable torque-down, even with a re-used washer. The lube limits galling of the washer.

Ř The lubed washer at 25 pounds is about the same ‘tightness’ as 33 pounds for a dry bolt and washer. So the lubed washer is no more likely to loosen than a dry washer. In fact, the lube gives a more consistent correct torque, than a dry assembly. The lubed bolt still ‘pops’ every time I remove it.


WHAT ABOUT A COPPER WASHER ON THE OIL FILL BOLT, INSTEAD OF AN ALUMINUM WASHER?
I prefer to use a copper washer instead of an aluminum one, to prevent the galling that occurs with the aluminum. The best Copper washer I have found is Toyota P/N 90430-24003. And it only costs $2.53 and seals better at a lower torque than an aluminum washer. This copper washer fits a 4Runner front differential case drain plug. The Acura aluminum washer costs between $4-5 at my dealer(s).


SAFETY WIRING THE DRAIN BOLT:
I used 0.033 inch soft 304 stainless wire. The bolt and washer are lubed, and torqued to 225 in-lbs (19 ft-lbs). The factory specification is 36 ft-lbs. Normally I use a copper washer, although it looks like I used an aluminum one the last time I did this. No leaks, and the safety wire prevents loosening. The low torque limits the steel bolt threads from wearing on the aluminum threads in the trans case.

I purchase 18mm copper washers from my local auto parts dealer, for less than the factory aluminum washer. The auto place is open at night, which my dealer is not.

JMOs -eof

ptrapper65

Great write-up!!!

I've done the Tranny fluid change twice now. One time I used the ATF fill hole and the other time the dip stick hole. The dip stick was easier since I planned it in advance and had a great fit with a tube and funnel. Now that I have that, I'll never try to get to that ATF fill bolt again.

Just my 2cents.

Once again, great post with a lot of info and tips.

737 Jock

Yeah, when I checked mine it took about 40 minutes to get the fan to run once. That's an ridiculously unworkable procedure and good reason to find the corresponding cold level. The small difference in volume between the low and high marks indicates how important it is to get the level correct. Thanks for your findings.

I also was able to drain just over 4 quarts. I did this by raising the rear of the car about 6 cm higher than the front.

ps Wouldn't mind seeing a pic of your safety-wired drain.

dcmodels

I asked one of the mechanics at my dealer how they do it, but did not get a clear answer ? I did note that in the setup procedure in the Maintenance Manual delivered with my car, that the procedure is to check that oil shows somewhere on the dip-stick when COLD. This is the check-list for pre-delivery of the vehicle. Based on this, I really wonder just how critical the oil level really is. Well, I try to get it between the marks on the dip-stick anyway.

I am pretty sure that my garage floor is level, so I am puzzled as to why my car drains more than the stated 3.5 quarts - perhaps that is just a guide in the book ?

Happy to do so. The car belongs to my (ex)wife, so I will not have access again until sometime in January. I do plan to post pics of all of the drain/ fill plugs that I have safety wired. I do not plan to wire the trans fill plug - cannot see how to do it without removing the air box which I am not going to do.

The only remaining un-wired plugs are the transfer case drain/ fill plugs, which I will wire when I replace the fluid next month.

Then I will post pics of all of the plugs showing where/ how they are wired. Thanks for your interest.

dcmodels

I believe that the warm-up procedure in the Owner’s Manual (OM) for reading the transmission oil level is in error. The 2009 Acura RDX OM publication P/N 31STK620 00X31-STK-6200 copyright 2008, states on page 343 item (1): “… Start the engine, let it run until the radiator fan comes on, then shut off the engine…”

I think that most people, myself included, understand the above to mean that the engine should be allowed to run at idle speed until the radiator fan comes on.

I believe that this section of the OM should read: “… Start the engine. Hold the engine speed at 3,000 rpm without load (in P or N) until the radiator fan comes on, then shut off the engine...”

Using this procedure will cause the engine to warm up in only a few minutes, rather than the 40 minutes or so required if the engine is allowed to warm up at idle speed. Running at idle speed for 40 minutes cannot be good for any engine.

I believe that the latter wording is the correct wording, because that exact wording is used in the following four examples taken from the RDX Service Manual 07-09 P/N 61STK02 PL 900.2008.06.09 Volume 1:

Crank Pattern (CKP) Pattern Learn Procedure (w/o using the HDS), page 11-5, step1

PCM Idle Learn Procedure, page 11-337, step 4

Throttle Body Test, page 11-391, step 4

DTC Trouble Shooting, DTC P2261 Turbo Bypass Control Valve Stuck Closed, page 11-421, step 8


These are only four of the many examples in the Service Manual which use the wording indicating that engine speed should be held at 3,000 rpm until the engine is ‘warm’.

As indicated in my original posting in this thread, I do not like to hold the engine at 3,000 rpm on a cold engine. So I use the procedure as indicated in my original posting: allow the engine to run at idle, until it indicates ‘normal’ temperature. Then hold the engine speed at 2,000 rpm until the radiator fan comes on.

My reasoning is that because the RDX does not have roller tappets, but flat followers, I do not like to hold such a high engine speed (3,000 rpm) on cold oil. But this may not be correct procedure. Perhaps holding the cold engine at a higher rpm than idle is better, since the higher flow of oil would better lubricate the tappet followers. This would only be (possibly) true at no-load. Obviously, no engine should be run at high rpm under-load with cold oil.

Any real automotive engineers (or engine builders) out there to comment?

JMOs -eof

737 Jock

Thanks for the research. I can certainly see the logic in accelerating the engine to warm it faster and I agree with you that it should be warmed progressively (idle, then 2000, etc).

I also don't doubt for a moment, that dealers and shops crank it cold and go right to 3000 -- their time is money (and it's not their car).

I looked through the Service Manual and found your references and others to warming the engine oil at 3000. My concern is that these procedures are all for warming the engine oil quickly to do some engine function or check that is unrelated to the transmission.

However, the Service Manual, Transmission section (2007, 14-238) also repeats the (idle for freakin ever) trans check procedure from the Owner's Manual and it's clearly different from the other cited engine oil warm-ups:

The specific instructions to use 3000 are not there, but they don't mention "idle" either. They want a certain ATF temperature and level for the check and it's pretty clear they don't want the car driven very far before, if at all.

They are using the radiator fan as an indirect indicator to set the ATF temp. I think the engine speed is important because the trans input shaft/torque converter will turn at that speed also -- circulating the ATF faster and heating it more -- affecting the level.

Logically, one should be able to use higher rpm initially to warm the fluids faster, but then let the engine idle for about 10 minutes until the fan runs. This should allow the ATF to settle back down. (But they don't say this.)

At any rate, the manual goes on to say that low ATF is far more critical than high:

Having done the Honda procedure once as a baseline, I've been checking the trans full cold, keeping it between the "T" and upper mark (ambient temp variations). Going on four years and two ATF changes, trouble free.

dcmodels

Quote:

Originally Posted by 737 Jock

… ps Wouldn't mind seeing a pic of your safety-wired drain.

OK, here you go – sorry it took me so long to crawl under the car and take a pic.













SAFETY WIRING THE DRAIN BOLT:
I used 0.033 inch soft 304 stainless wire. The bolt shoulder and copper washer were lubed with trans-fluid, and torqued to 225 in-lbs (19 ft-lbs). The factory specification is 36 ft-lbs. No leaks, and the safety wire prevents loosening. I purchase 18mm copper washers from my local auto parts dealer. The auto place is open at night, which my dealer is not.

The low torque limits the steel bolt threads from wearing on the aluminum threads in the trans case. And after doing several drains/ fills, I have never found the bolt to be loose. It is tight every time, but pops loose easily.

I drilled 1/16 inch holes through the four sides of the bolt head, instead of two holes straight through. The opposite holes do not have to be exactly aligned. I found this easier than trying to drill a straight hole all of the way through two sides.

The attachment hole in the case web is also 1/16 inch diameter, with the edges (of the attachment hole) beveled with a larger drill bit. The ‘inside’ hole is beveled at a slight angle, since there is no way to access the hole ‘straight-on’.

The safety wire is pulled from the 3-o’clock position on the bolt head. The 9-o’clock position is too far around clock-wise. And the 6-o’clock position is too close to the case web attachment hole. To wire the plug, twist the wire pulling straight down from the bolt hole, at the 3-o’clock position, until enough length has been twisted. Then, bend the length around the bolt head, and pull one piece of the wire through the attachment hole in the web.

Well, just try it, as describing how to do it is awkward. I usually need a couple of tries each time I do this, to get the correct length, without too short or too long a twisted run to the attachment hole in the web.

Before I started safety wiring this bolt, I would paint a strip of red finger nail polish across the bolt head, and onto the case, to indicate if the bolt should begin to loosen. The red marks do not align in the picture, because previously I was using an OEM aluminum washer, which is twice the thickness of the copper washer used in the picture (allowing the bolt to turn further).

Make sure that the pig-tail (from the web retaining hole), is positioned/ bent-up, so that it will not rip your (or your mechanic’s) hand, face, or eyes when working under the car. The twin tips of the pig-tail can cause you to require stitches, or even blind you, in an instant.

Finally, after each time that I drain the oil and replace the bolt, I smear the bolt head with silicone grease (AKA dielectric grease), using a Q-tip. This prevents the bolt from corroding. The grease is clear, and will not wash off, but is easily wiped off. Buy the larger 3 ounce size rather than the small 1/3 ounce tubes – 9 times the amount for twice the price.

--eof

737 Jock

Nicely done. Looks ready for flight!

zekerdx

Lots of great info here, Thank you!

superblast

Amazing write-up! You and 737 Jock are responsible for me taking on more than just oil changes with my RDX and I really appreciate that!

Just a quick clarification though, when running through all the gears the night before taking a cold reading, are you braking the entire time and just switching between selections? Or, are you actually driving a little in each gear?

Thanks again for the thorough write up.

dcmodels

If you have NOT drained and changed the trans oil, and have been driving the vehicle daily, then no special process is required before taking a cold trans oil level reading. Well, the vehicle must sit at least 8 hours, and preferably overnight.

If you are referring to the above section of my original post, go back and re-read that entire section. Keep in mind that this is a temporary CHECK-reading, after a drain-and-fill of trans fluid. And BEFORE driving the vehicle any significant distance.

To get a valid COLD or HOT oil level reading, the following is required.

And I can see that the above is a bit confusing. If the trans oil has been drained and refilled, it is necessary to FIRST follow the procedure that I described for taking a CHECK-level reading after a drain-and-fill. I engage each gear and PARK and REVERSE, for about 3 seconds during this procedure, while the vehicle is STATIONARY and BEFORE DRIVING.

THEN follow the procedure described for a factory FLUSH procedure, between each of the three drain-and-refills. This procedure has been published several times on this forum, but rather than search for it and give a link here, I will just repost the procedure below.

The reference is to steps 3-7. Those steps describe how to run-through all of the gears correctly. Note that the procedure describes doing this on a lift. I do it by driving the vehicle about 10 miles total.

And of course, I stop to engage reverse and park, pausing in each for 3 seconds or so. And please stop somewhere safe, such as a parking lot, not just on the side of the road. I also drive in reverse about 100 feet. Actually, I just circle back home, use my condo parking lot, and my own driveway.

Finally, allow the vehicle to sit overnight before taking your valid COLD or HOT reading.

Here is the factory FLUSH 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. [ed: this may require a speed of 50-60mph, so do this on the freeway.]
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.

---eof

Kaze66218

Can't wait to do this, the dw1 aint working for me. Dunna like it.

737 Jock

^^ I haven't switched to DW-1 yet. What sort of issues are you having with it?

superblast

Thanks again dc... your detailed explanations are very helpful.

H22A_CD5

iTrader: (3)

More info please? I just bought a case and was getting ready to do this saturday.

mrclemson

I checked the transmission fluid level over the weekend when the car was completely cold. It was about 6mm below the lower point on the stick. We had the fluid replaced at the dealership in March 2010, when it had about 28K miles; right now it's at 45K. I am not sure whether this is normal after 2 years and 17K miles, I somehow recall that I checked the level after the work was done, and honestly I don't usually check the transmission fluid level. My garage is spotless, so it doesn't seem like it leaked.

I am wondering whether that’s caused by the cold whether. Being in Mid-Atlanta, it’s not that cold. The normal working temperature for transmission is around 90C, if I measured at 5C, and assuming the thermal expansion coefficient for the transmission fluid is the same as new engine oil (0.0007/C), the difference in volume is about 6%, since RDX takes 7.8L fluid, that’s about 0.46L.

Per dcmodels’ observation: 1mm ~= 1oz, for me, 6mm ~= 6oz, does this sound normal to folks? I assume that’s why Honda wants us to check the fluid level when it’s hot. I actually topped it off by setting the level at the mid point between the high and low marks – I am just that kind of guys who want to see everything perfect.

proof

I want to do a 1x drain and fill with every oil change.
In which manner should I raise the car to get the most fluid out? I don't have access to a lift, and usually I just use ramps to lift the front for oil changes.

wusty23jd

I'm bumping an old thread here, because there is some good information to read through and personally, I've always found that reading the transmission dip stick is a huge pain.

With my TL, I always tried to take a hot reading after running through all of the gears and waiting for the fan to cycle on once.

This is a first time I've tried to take a true "cold" reading. My wife's RDX has been sitting for about 24 hours and this is what I found. It appears that this is a bit on the low side? Maybe I'll take it for a spin and try reading it when it's "hot."

CSmoney28

wusty23jd

To reiterate, the RDX did sit for about 24 hours, so technically it was "overnight." It was also parked in the garage (aka a level surface).

The fluid looked pretty good and did not contain a burned smell. However, I'm still going to replace the fluid and perform a 3x3 drain and refill for peace of mind.

I'm just trying to confirm if the above "cold" reading is accurate, so I can accurately determine fluid levels. The picture above was after the third pull.

wusty23jd

I never followed-up on this, but I just wanted to mention that after I let the RDX run and let the radiator fan cycle once through, I waited about 60 seconds before I checked the transmission fluid level. The "HOT" reading is pretty much right on the money, which makes me feel more comfortable when I do a 3 x 3 drain and refill in the upcoming weeks.

CSmoney28

mascalif

Great write up. On my 2016 they buried the dipstick in my RDX under fan shroud plastic. It is very hidden and difficult to use. The dipstick itself is also "cheaped out" with no hash marks, just 2 holes and a "hot" between them.
The trans fill plug is easy access in my engine bay. A 16" - 18" extension for the socket and a long funnel for filling makes short work of adding fluid.
The drain plug is nicely extended beyond the wind/rain protecting plastic shield making it easy to get every drop.
My fan never comes on at idle. I just warm it up to 7 bars on the temp gauge and call it good. I also indexed the dipstick with a file for a cold reading.

CSmoney28

At least they gave you a dipstick to your transmission, a lot of companies don’t even do it anymore.

udelslayer

This is directed towards Wusty23jd - did you measure and if so, what volume drained from the transmission? I'm trying to figure out if somewhere I took it may have put .5qt in it without telling me. I found that my measurement is more than an inch over the top mark if its sitting cold the next day or warmed up. I'm going to change it since its due anyway, but i'm really hoping this didnt wreck the seals after having been like this for 5 months.

thanks
j

wusty23jd

Yes, I did measure the transmission fluid each time. Please check my progress thread here:
https://acurazine.com/forums/first-g.../#post16359249

Mymeasurements were the following:
Before you begin the drain and refill, I recommend that you use a siphon to lower the fluid to an accurate reading. Below is a similar tool to what I purchased last year:

If you let the vehicle sit overnight, do the siphoning right away in the morning BEFORE turning on the car. That way, you can get a true cold reading and you can perform a proper drain and refill once the transmission fluid level is back down within range. Once the fluid is within range, you can proceed to perform your first drain and refill. Measure how many quarts you drained after the first drain and go from there. Your life will be a lot easier if you get the fluid level within spec BEFORE you start this whole process.

udelslayer

Thanks for the info wusty. I read your post 34 (and others and lots of details).

Are you assuming I'm doing the 3x3? I'm just swapping the fluid once and getting it to proper level.

Just wanted to clarify - Your overnight cold reading is at the top of the hot mark before starting the vehicle? From that point, initial startup and immediately measuring will be lower than the existing line because the viscosity will be coating the walls and bodies and by the time it gets to temperature, its expanded and lost some viscosity and will be in the dipstick's range of 8oz.

Not trying to argue, but trying to understand the logic. What would it matter if I siphon the fluid? I'm pretty certain that the stupid shop I had to take it to added .5qt (16oz) of fluid if the cold measurement is way up over the full hot marks on the stick. This means its been driven like this for a month. I am 100% sure I did not add fluid to the car since the last time I did the 3x3 at 66k.

I notice you used a 1qt cup, but the image of that isnt coming through for some reason. I drain into a shallow pan since you dont have to raise the car to do either the oil or the ATF. I have a 5qt graduated bucket you can get from wally world to take a measurement when I drain it. I know those measurements are good as I just did my Tacoma's ATF with it. I'm expecting to see 4.5qt come out when I do it on Saturday. Would it be as effective to put 3.5-3.75 back into the car and warm it to operating temperature, then adjust from there? I guess it couldnt hurt to remove the fluid with a pump a, but I am pretty sure its at the wrong level. There is no point in trying to argue with a shop now, but this is why I dont go to mechanics if I can help it. According to techs, they overfill these all the time and argue with the customers about it. I think this is the same unit in the MDX and a few other vehicles so the procedures are identical. The only thing special about the RDX these days is the axles, and I'd recommend getting OEM units if you ever have to do them.

udelslayer

I had to read the above posts again. Your fluid is below cold when overnight and then when warmed at the top of hot. Thats good.

Mine is way above hot overnight and still above hot when hot. If the points are 8oz, then the overfill is 16oz. My past fill was just about 4qt, which seems to be the right amount. Car has been problem free....so I forgot all of these little nitpicks.

Post 34, item 6 from your other thread. Is that level from a cold motor and hasnt been turned on yet?

J

wusty23jd

Okay, so the reason I recommended you get a siphon is so that you can remove some of the excess fluid via the dip stick in the engine bay. Your levels are extremely high, so before you perform any type of drain and refill, I recommend to FIRST get the fluid level within range. That way, when you drain all of your old fluid via the drain plug (below the vehicle), you can measure how many quarts were drained. This will make it much easier to fill your transmission with the appropriate amount of fluid. By measuring precisely how much fluid comes out, you are reducing some of the guessing you have to do when it comes time to refill.

When I drained my fluid, I used an oil drain pan (similar to you). However, afterwards, I poured the transmission fluid from the pan into a 1qt cup, so that I could accurately measure how much fluid was drained. I did not drain the fluid from the vehicle directly into the 1qt cup.

Also, I think your logic is backwards. When transmission fluid gets hot, it will expand and that is why the "hot" reading is higher on the dip stick.

Originally, my true cold reading was a bit below the cold marker. When the fluid heated up, it expanded, and was just below the hot marker. After I performed my 3 drain and refills, my cold reading was a bit above the cold marker. I was hoping the level would be closer to the cold marker, but after trying to get it right with my siphon like 3 or 4 times, I was okay with it. My understanding is that a little excess won't hurt, but having waaaay to much isn't good for the seals.

udelslayer

Yeah, the seals and the pressure on the clutch packs are what worry me. I dont think this unit has bands. The fluid looks, smells, (and probably) tastes great. I'd assume its been this way for about 5k miles since my last oil change. From what I have observed, the expansion raises the read by about 10oz of measurement. I only checked it because I thought I saw a leak, but it turned out to be something else. While I'm kinda pissed at the shop and at myself for not checking over their work earlier, at this point all I can do is make it right. I dont think that you can go wrong with 3.5-4.0qts of fluid considering EVERY MDX, TL, Odyssey, and even the RDX fluid change procedure uses 4qts for a drain/fill. There are a few examples and videos out there. FWIW, I picked up a fluid pump today and may do your suggestion. I understood you drain into a pan and then fill the cups individually. Instead of cups, I have a graduated bucket they sell in the paint section of Walmart and Lowes/HD. It measures 120oz (3.75qt) accurately, and I've extrapolated the markings for 4.25qt. It has a 5qt capacity. I think what throws people off is that the cold measurement is below the cold marks on the dipstick and it probably could have used a longer dipstick to have a cold range measurement like my Tacoma (which has both hots and colds). I think people second guess this cold reading because its not a reading and looks lower than it is. I think Honda assumes there is always a specific amount to replace to reach this same measurement. Doing the measure and refill is an old school thing that people often did when they siphoned the fluid out of the dipstick. When you take the car to the dealer, they're not going to let it sit for 24 hours to let the fluid contract, hence they fill with 3.5 and then heat that up and measure. You're higher than the original reading, but thats not anything to worry about because apparently all the service shops end up with that same scenario once they break from factory fill because they do the same thing. Even you were measuring 4qt with the drains/fills. Originally, my fluid levels were exactly the same as yours. Below the cold dot on a overnight, and then right below the hot dot on a hot reading. When I did my 3x3, I put 3.75 in (instead of the recommended 3.5 in the manual) to bring the cold reading up. I think you can get away with 4.

I am expecting to see about 4.50qt when I drain it Saturday. I'm probably going about this way too long and complicated....I'll post my results when I do this. I think I've read every post and watched every available video on the topic because I had a bad transmission experience once...but all dodges are bad experiences.

Thanks for your detailed information. If when I change it I have the same result, I will siphon till perfect, but I think I'm splitting hairs. They dont put good information out there because they want you to take it to a shop for service. Just think the new 9spd unit has clutch packs and dog teeth engagements....and the fluid is Acura ATF 3.1 and COSTS $40 per qt!!! Man, I really hate newer cars, they're so complex and expensive now.

BTW, found this video of a guy who uses a condiment bottle to insert in the dipstick tube and then a funnel inside that. Good hack

udelslayer

So are you ready for this one?




At least 6 motherloving quarts. I had to get a bigger measuring bucket to hold all the fluid that came out.




My guess is somebody did a double change on the fluid based on the old 3.0qt refill and dumped 3 more in it because they thought it was a change. I should probably at least make a record of it with them. It is a professional transmission shop that others have claimed do good work. First mechanic I've had to use in 25 years. He never said he put fluid or did anything with fluid when I had him change the pitch mount. It could be an honest mistake or it could be something else.




I put 3.5qt in and it brought it just 2mm below the bottom dot. I tried to warm the car for almost 30 minutes in idle and running up to 2-3k rpm for a few seconds at a time and couldnt get the fan to kick on (and I believe it and the switch works). I got it to gauged operating temperature and didnt notice much of a change. I put 3.75 in and it looked fine, so I put the full 4 qts in and it brought it right to the bottom dot at least at this temperature. I'll wait overnight take a cold reading and then probably have to try and warm it up again or take it around the neighborhood. I'm sure I'll be doing this again in a couple weeks to freshen the fluid. The plug had the typical sludge on it. Fluid didnt smell but it was darker than it should be.




I think because I'm draining it level that 4qts comes out whereas the instructions in the FSM on 14-198 (and I'm guessing) may be based on raising the front some which would drain less fluid due to drain being in the front.

udelslayer

The book says that after its warmed up, to correct the fluid by adding more if necessary so thats what I did for a total of 4.25qt but it looks normal now. FWIW, I read somewhere that the fan triggering means that its 90C (194F), which is pretty hot. Using my Veepak OBD adapter and Torque Pro, I can measure the coolant and trans temperatures to ensure that I reach the right operating temperature before checking the fluid level. This is a pretty common procedure these days like when sealed trans tacomas with WS fluid need to reach a specific value before the trans overflow can be measured. They should have discussed this in the FSM, but its kinda non-specific about the values for some reason. Using some 1/4 OD tubing and that condiment bottle, it works excellent for putting new fluid down the DS hole. You dont need another funnel to catch what you pour either. It keeps it super clean and throw that whole contraption in a bag for later use to keep the lint out.

CSmoney28

Thanks, for all the information.