DIY - Transfer Fluid change
 

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 :ugh:. 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. Hypoid gear oil, API classified GL4 or GL5: 430 ml (0.45 qt). SAE 90 above -18 C (0 F) and SAE 80W-90 below -18 C -- or --
2. If the above is not available, one quart of Mobil 1 or Castrol Syntec synthetic 75W-90 will do fine.
3. A hand pump for installing the oil.
4. 3/8" drive ratchet and short extension.
5. Small torque wrench (preferred).
6. Spirit level.
7. Eye protection, face protection, gloves and protective clothes.
8. Drain pans, newspapers, rags, etc.

To change the Transfer Fluid, insure that the engine is cool or only slightly warm. Then make sure the RDX is raised and level. This is so the fill port will hold the correct amount. Place a spirit level along the rocker panels, under the doors:

http://img198.imageshack.us/img198/4552/tx1r.jpg

The transfer unit is attached to the rear, right-side of the transmission. It has a fill plug facing forward and a drain plug on the bottom. It may be dirty, but it should be dry with no evidence of leaks:

http://img87.imageshack.us/img87/8873/tx2e.jpg

Always loosen the fill plug first. This is to insure you can refill the transfer before you begin to drain it.

The transfer fill and drain plugs are identical and only require a 3/8" drive to turn (no sockets). Using the 3/8" drive ratchet and a short extension, break the torque on the fill plug. Remove the fill plug to check the oil level. It should be just at the bottom of the fill port and some may drip out. Reinstall the fill plug loosely.

Prepare a container to catch the fluid and remove the drain plug. I use a container with a sight gauge so I can measure the old fluid quantity:

http://img706.imageshack.us/img706/9713/tx3u.jpg

Here is the sight gauge showing exactly the 430 ml (.045 qt) of drained oil that the RDX manual specifies:

http://img121.imageshack.us/img121/7775/tx4r.jpg

When it stops dripping, clean the transfer and any traces of oil. This is to facilitate the leak check later. Replace the drain plug seal washer with a new one (part 94109-20000). The fill plug uses the same washer, but it may last through 2 uses if it's not over-torqued. Here is the seal washer package:

http://img409.imageshack.us/img409/1048/tx5w.jpg

As an option, apply a bit of thread sealant to the plugs. Install and torque the drain plug enough to crush the seal washer slightly (44 N-m, or 33 ft-lb).

I use an outboard motor oil pump to fill the transfer. This screws right on to the gear oil bottle and the metal fitting on the hose end fits snugly into the fill port. For minor top-offs, I use a MixMizer syringe. Both are pictured below and are available at auto parts stores. (For the SH-AWD differential service, I have a second outboard motor oil pump and MixMizer syringe. This prevents contamination between the gear oil and ATF-Z1.)

The RDX Service Manual calls for SAE 90 gear oil above -18 C ( 0 F) and SAE 80W-90 below -18 C. That's pretty hard stuff to find. I have used Castrol Syntec and Mobil 1, 75W-90 synthetic for several years with excellent results:

http://img837.imageshack.us/img837/2473/tx6s.jpg

Position a container under the transfer to catch overflow. Pump the gear oil into the transfer fill port, using the sight gauge on the bottle to monitor the progress. The RDX Service Manual specifies 430 ml (0.45 qt) to the bottom of the fill port.

http://img827.imageshack.us/img827/8585/tx7k.jpg

When it begins to spill out, let it slow to a trickle and install the fill plug (44 N-m, 33 ft-lb). Wipe everything clean. Clean up all tools and items. Lower the car and take it for a drive around the neighborhood -- get it up to temperature. Now look under and check the transfer again for leaks. This is why cleanup was important earlier -- the bottom of the engine must be clean and dry to identify any leaks.

Excellent writeup as usual sir! Bravo :)

Thanks wspy.

I should mention that the standard torque settings apply to new seal washers only. If re-using a seal washer, run it down to contact, then only about 30 -45 degrees farther turn (up to 1/8 turn) to seal it. Don't over-torque it. It can always be tightened a bit, if it seeps on the leak check.

Cool was planning on doing this this weekend along with DW1 in the transmission and rear diff as well as engine oil.

Helm's says to fill it until it starts to come out the fill hole.

thanks for the great diy guides, very detailed. do you happen to know what the oem fluid is? also will the royal purple max gear oil as well?

http://royalpurple.com/gear-oil.html

also do you plan on doing a diy for coolant and power steering?

Royal Purple isn't that great, I am currently using Syntec 75w90.

As far as I've been able to determine, the transfer oil is one that there is no "genuine" Honda OEM fluid for. The Pilot, CR-V, Ridgeline, MDX and RDX manuals show only the specification listed above.

It is nearly impossible to find this spec. The dealers probably use bulk stock of whatever 90-ish oil they get a good price on. Most DIYers use a good synthetic 75W-90.

^i only found 1 80w-90 gear oil by mobil one. will this work?

http://www.mobiloil.com/USA-English/...us_80W-90.aspx

Well, the weight of 80W-90 is per Honda spec but I'm a little put-off by the statement on the Mobilube HD site:

This stuff is clearly heavy-duty for commercial trucks, hence GL-5 only.

Honda specs GL-4 or GL-5. I would stay with a gear oil that is also spec'ed GL-4 or GL-5.

The commercial grade GL-5 is designed for high temps and pressures -- which it will not reach in the RDX -- it will not be in its designed service range.

^ ah i see, didn't read that part. do you plan on making more detailed diy like power steering fluid and coolant?

I live in the snow belt, and both my local dealers state that they use Valvoline non-synthetic 80W90 bulk.

I personally use Mobil 1 75W90, which is readily available from any of the local auto parts stores. The Mobil 1 web site tech data page for this product, does state that it can be used for GL-4, but is primarily intended for GL-5 (my understanding of the data page). I personally would not use it when ONLY a GL-4 product is required. I think it is great for both my RDX transfer case, and my Chevy truck axles.

The GL-4 spec is intended to protect 'yellow' metal, such as bushings etc. GL-5 products often will 'attack'/ corrode these metals. I am guessing that the additives in Mobil 1 75W90 are such that brass/ bronze (yellow) is not at risk, assuming that these metals are in the RDX transfer case. So I like the Mobil 1 because of the RDX Acura GL-4/ GL-5 spec.

For those who are interested in such things (I am an engineer), there is a 'white paper' comparing gear lubes, published by AmsOil. Note that I have no relationship to that company, have never used their products, and found this information while searching for something to use instead of the $38/ quart GM OEM gear lube, for my Chevy truck.

I have seen various links to the document, but here is one on the AmsOil site.
http://www.amsoil.com/lit/g2457.pdf

Use this stuff. There is no higher quality gear oil available on the market.

http://www.amsoil.com/storefront/svg.aspx


This is Amsoil's severe gear lubricant and it can be used in API GL-4 and GL-5 applications.

Again, another great write up. I'm planning on using this method as soon as I can properly put the RDX on 4 jack stands.

Thanks for that info dc.

It's the active sulfur in the Extreme Pressure additives in the GL-5 which has corroded yellow metals. They now claim that modern formulations of GL-5 are inhibited from attacking yellow metals.

From: Monitoring Active Sulfur in EP Gear Oils
It's worth noting that GL-5 does contain EP additives which could attack yellow metal but are inhibited.

We don't know if the RDX transfer contains any yellow metal bushings or parts. Honda says we can use GL-4 or GL-5. Translation: GL-4 is good enough, but GL-5 won't hurt. This could be because the transfer contains no yellow metals or because the newer formulations are safe. But I've been using Mobil 1 and Castrol Syntec with no apparent problems for 4 years.

Keeping in mind that EP additives can decompose under high temperature and form metal sulfides, I change the transfer every 30k with the tranny.

Perhaps, but my skepticism is why I would use only a GL4 when a GL4 ONLY is specified, such as for a manual transmission (does not apply to our RDX). And the RDX transfer case holds only 1/2 quart, so I wonder just how hot it gets pulling a looong hill outside LasVegas in the summer?

And I always use only a GL5 (or GL4/5) rated oil when there is a hypoid gear involved, as in the RDX transfer case. For myself I would never use only a GL4 oil when there is a hypoid gear in the case. For those wondering what is a hypoid gear, and too lazy to check Wiki, it is a set of gears cut to transfer power direction by 90 degrees - in this case, from the direction of the front drive axles (tranverse) to the direction of the length of the vehicle (longitudinal) to the rear drive shaft. Now, what I find amazing, is that the front differential (which has 'sort-of-but-not-really' hypoid gears), runs in ATF, which is why I change the transmission fluid more often than the MID specifies.

That seems like good advice.

Good call. I like Pennzoil Syncromesh for my manual trannys.

The rear diff has hypoids and runs in (or did) ATF-Z1 too --go figure.

Just performed this while doing scheduled maintenace..thanks for the info/writeup :thumbsup:

Great write up and overall info as usual, 737! I changed my tranny, transfer case, rear diff fluids and engine oil this weekend. The car is smooth as butter now. Thanks!

Great DIY , I was able to do it without raising rdx. I used mobile 1 75w 90 syn gear oil. I think I found one that matches exact requirements in manual. See link: http://matrixsyntheticoils.com/datas...0_gear_oil.pdf

Maybe try that stuff next time not sure if it's synthetic though.

737, your DIY's are just great, among the best ever and many thanks for your time and efforts on them.

So if you re-fill 'til it drips anyway, is keeping track of the amount that came out important?

^^

Not really.

It's just helpful to verify that it wasn't leaking. But if the transfer case is not dirty and greasy, that's pretty good evidence that it wasn't leaking also.

Using Amsoil
 

I am using the Amsoil 75W-90 synthetic as suggested by DigitalSniper on this thread. http://www.amsoil.com/shop/by-produc...ont%2fsvg.aspx It is rated gl4/gl5 and has excellent low temp. flow characteristics. Since I live in a low temp environment in Colorado where temps can get as low as -25F it should be a good choice. Excellent thread 737jock.

Need new pump for bigger bottle mouth
 

I had some difficulty getting the gear oil into the transfer case with my standard Walmart pump since the Amsoil bottle mouth is larger than most quart containers.:annoyed: I need to buy one of these to do the job next time for $11 from Amsoil: http://www.amsoil.com/shop/by-produc...?code=G2039-EA

I actually used a different Amsoil but I think it should work. I used this stuff: http://www.amsoil.com/shop/by-produc...?code=FGRQT-EA They say it is okay for GL4 & GL5 and it shold last forever!

Using Amsoil
 

I received the following email from Amsoil Technical Support:
"The Long Life 75W90 is one of the recommended gear oils to use in this transfer case. It will be equal in performance to the Severe Gear lube in this application."

considering how little the front transfer case takes, I found I have over .5 quarts of each.... lets get some opinion on what I should put in...


redline 75w90 mt-90 gl4
http://www.redlineoil.com/product.aspx?pid=46


redline 75w90 gear oil gl5


amsoil 75w90 gl4 gear oil
http://www.amsoil.com/shop/by-produc...r-lube-75w-90/

I just changed my transfer fluid and used genuine Acura. PN# 08200-9014A. $15 at my local dealer for a qt.

Good Write up. Then how to reset service code B13 in 2007 Acura RDX?

How to reset 2007Acura RDX B13 code?

You're referring to the maintenance code displayed? Cycle the display to the oil life%, hold the reset button for 10 seconds or so and the option to reset will come up. Select reset and hold for another 10 seconds or so and you're done.

FYI i have been using Mobile 1 75W-90 , but on next transfer fluid change coming up i have purchase the 80w-90 synthetic from Amsoil on their site :

https://www.amsoil.com/shop/by-produ...?code=AGLQT-EA

Thanks for this nice write-up 737 Jock

I changed my transfer case fluid last week on my RL.. Since the local auto parts didn't have Mobil1, I ended up putting Royal Purple instead..

anyone have a cached or downloadable version of this with pictures?

https://cimg8.ibsrv.net/gimg/acurazi...3e7979555.jpeg
https://cimg9.ibsrv.net/gimg/acurazi...b12ac403d.jpeg