I have a 2020 RDX SH-AWD. I bought it this past September from a Kia dealership. It had 24xxx miles on at the time I bought it. It didn’t come with any maintenance records except for the car fax that showed it had been to the dealer a few time when the previous owner owned it and the Kia dealership gave me documentation stating the front rotors and pads had been replaced and an oil change while it was at the Kia dealership.

After doing a lot of reading here I decided at 30,000 I would change all the fluids because I have no idea if any of them had been changed except the engine oil. The only code in the maintenance minder was A 1 2, oil, oil filter and air filter. I replaced the cabin and engine air filter very soon after the purchase. I purchased all of the oils I needed and the crush washers, again from reading various posts.

Yesterday I jacked the car on to jack stands and got it as level as possible. The engine oil and filter were very easy. Then I started on the trans fluid. I had watched a few videos before beginning this work and read a bunch of posts but didn’t realize there are 3 different plugs for the trans and therefore, did not have a crush washer for the “sight” plug. I pulled the “sight” plug first (small plug, 12mm), thinking it was the fill plug. Fluid began coming out of this hole. The fluid looked good, but I was surprised to see this. I didn’t have something ready to measure how much came out, but at a guess, I would say about 1/2 a quart. Once it stopped, I found the large fill plug and removed it, and then the drain plug. I don’t know if this fluid had ever been changed, but it looked very good. The drain plug magnet had some black sludge on it but seemed normal compared to other times I’ve done trans services on other vehicles.

When I refilled the transmission using a quart bottle fluid pump, I decided to lightly re-install the sight plug for the first 4 1/2 quarts so not to have fluid run out while pumping. Occasionally, I did lose some fresh fluid that came back out of the fill hole and once or twice the hose came out of the hole while filling. I think I lost less than 1/4 of a quart total during the filling process. When I had about 1/2 quart left, I pulled the sight plug and oil came out. At this point I became a little concerned. The Acura dealer sold me 5 quarts of ATF 2.0, I’ve read on posts here the trans takes 5 1/2 quarts, when I pulled the sight plug oil came out and now I have less than 5 quarts in the trans and its running out of the sight hole. So I fully installed the sight plug, added a few more pumps of fluid in and reinstalled the fill plug.

I am wondering if it was overfilled from the factory…. And is roughly 4 1/2 quarts enough?


Next I tackled the transfer case. The fill plug was super tight and not very easy to break loose, but I got it. Then the drain plug. This oil did not look very good. It was brownish/gold colored but fortunately not “sparkley”. I doubt this had ever been changed. I installed the drain plug and began filling. This was a mess. Unless I went VERY SLOW oil would back out the fill hole. Even with rags tucked in there, oil ran out and on to the exhaust. I had 1 quart of the gear oil and fortunately it only take about .61 quarts. I believe managed to get it filled to the proper level, the slightest amount added (slowly) came right back out. So I wiped up the area and installed the fill plug.


The rear diff was pretty easy after removing the spare tire. Only problem is I bought 3 20mm crush gaskets and 3 17mm gaskets. It appears what’s needed is 4 20’s and 2 17’s. So being I was short 1 20mm gasket, I reused the fill plug. It seems to be holding ok.

After getting all fluid levels correct, tires rotated and while the car was in the air, I started the engine, (no low oil light or any other warning light) and I ran through all of the gears (D, N, R, P) many times and I also let the tire spin a little towards the end of this process. I check for leaks and with the exception of a little still weeping from the mess I made with the transfer case, all was good, so I lowered the car down. I went for a short ride, about 2-3 miles and all seemed well. When I got home I remembered to reset the transmission (ACC mode and holding throttle down for 30 seconds). I will drive it more today.

So what do you guys think about how the transmission fluid change went?

All in all it wasn’t a terrible job, but I’m getting older and I was a bit sore after 1/2 a day getting under and back out from under the car. Jacking it higher would have been helpful. And I’m thinking next time all fluids need changed at the same time and based on cost, I might let the dealer do it.

 

Did you have the car warmed up (radiator fan cycles on at least two times) and run through the gears (P,R,N,D,S,2nd,S,D,N,R,P for at least 3 seconds each) before shutting down and checking the transmission fluid level?

Owner's manual says 5.1 quarts for AWD transmission. I'd be a bit surprised at only ~4.5 quarts required to fill. I wouldn't be surprised at a bit of an overfill from the factory.

Regarding the sight (level) plug -- was it a bolt and separate washer, or a bolt with a captured washer? If separate washer, do you know the size? Thanks.

 

Attofarad,

After reading your post I picked up another quart of the ATF 2.0 and 20mm crush gasket. I got the RDX to full operating temps, ran it though ALL the gears multiple times and then drove the front end onto ramps and jacked the rear until the car was level. I pulled the sight plug and nothing came out. I pumped in approximately 8 ounces (I will try to post a picture of the side of the bottle) when fluid began to come out of the sight hole. I installed the plug and button it all up.

The sight plug did not have a crush gasket, however the IPB shows a gasket and its part number is 90471-59C-000. Next time I do this job I will get the crush gasket. When I was at the Acura dealer this morning they did not have that gasket available.

While the car was up and level, I pulled the rear diff fill plug to check the level. A little came out, so I installed a new gasket and reinstalled.

All good to go now!

Thanks for your reply and advice!

 

Hi, I see we are on the thread of the Transfer Case of Acura, I have the 2011 Acura MDX and recently just changed the Transfer Case fluid for the 1st time, everything is fine except that I notice the Drain plug is not MAGNETIC. So my question is: Does the Drain plug of the Transfer Case in the 2011 Acura MDX originally have the magnetic plug or not at all? Thanks very much for the advise to clarify this mystery as I tried to watch several YouTube videos of this subject but none has shown or mentioned about the Transfer Case Drain plug has magnetic or not.

 

Hi Tony, I changed the fluids in all 3 components of the "drive train" on my 2019 RDX last year. I recall noticing that only the automatic transmission drain plug had a magnet.