Fluid Maintenance Transfer-case beware

KrisKringle

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Mazda CX 9 Grand Touring
My 2008 GT awd is at 61000 miles, I did some maintenance , I have read up on this ford AW21-27-500N-9U transfercase, so 3 months ago I pulled the fill plug and siphoned out as much fluid as I could with my suction gun. The fluid was black sludge with a viscosity not even remotely close to the specd 75-140. I only got .25 qts out and refilled with mobil 1. I then ordered my atf for the transmission along with a mityvac. I changed the transfercase again last night, the mityvac sucked the fluid out much better then the suction gun (for those unaware the transfer case has a fill only plug, no drain plug). I pulled fluid out until the mityvac run dry. Then I refilled it with Mobil 1 along with 2 oz of Autorx, this is a cleaner and seal conditioner. NOT a seal sweller I have used this with great results in the past particularly on rotating seals.
Here is the gist for those on the transfercase, they seem to have a high failure rate I have read about transfercases being dry to being full of sludge. Here is my analysis, the transfercase is built adequate with the exception of fluid capacity. It is just not enough for something turning all the time near the engine with such heat. They have failed with this. It either needs more fluid capacity or a drain plug and a service recommendation of 30-60k, rather then the super lifetime fill designation. The transfer case failures to me are from fluid overheating and becoming compromised to the point it cooks to sludge or to the point the seal drys and then whats left leaks out.
The fluid that came out this time was black, viscosity on the oil was notably thicker then 75-140, but much better then what originally came out three months ago. I will be changing mine yearly after I change this cleaning phase of autorx out, if I feel it can go longer ill do so. But for those desiring to keep these vehicles beyond 100-200k id recommend doing a fluid change immediately or saving for a new transfercase, This is a failure in engineering ford has this in many vehicles and they all have seal problems and early failures.
Transmission fluid I did a simple drain refill, I measured exactly what I drained and refilled with the same amount, which for me was 3.3 qts. I refilled with Mobil 3308 the fluid specd for out transmission, NOT a universal, the fluid came out dark, not burnt but darker then I expected.
The rear axle was as to be expected for a 60k gear oil.
Now for those that will argue the lifetime fluid is lifetime and im wasting money, that's your opinion I have mine, but which one do you think will still be running original transfercase and transmission at 200k care to wager?
I have to say I have worked on all my cars and this car seems like one step off madness, some items seem to be so well thought out and engineered and some are last minute disasters. I also am alarmed by the high number of problems and complaints. I am more used to Subaru's and honestly I am a bit disappointed in the engineering of this "Japanese" vehicle, its a let down on quality and thought to me, while im being meticulous on maintenance and am preparing to own this for the long run, I am not fully decided I want to we passed up a Tribecca for this and while I love the package and overall features and to me that is why I went it over the Tribecca I am not sure it will equal its reliability.
 
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Kris,
Thanks for sharing.

I am not sure if dealer will be willing to do fluid change for me.
Not everyone can or is wiling to do what you did.
I will ask however at my next dealer visit.
 
Kriskringle, while you are at it get yourself a scan tool. I am already on my second bad coil and this one cost me since my extended warranty expired a month ago. It is not cheap especially if it is the rear bank. I decided to have the plugs changed as well since the manifold was off when they replaced the coil.
 
I have one and do all my maintenance but if this vehicle starts eating parts like some I see on here, is gone. I love the vehicle but wont stand for mediocrity.
 
As long as proper maintenance is done, I don't see issues within reasonable mileage.
 
KrisKringle, thanks for sharing, but next time add some photos how you did it, the tools you used :)!
 
this is why I got a FWD version. I like the Ford 3.7, but didn't want the headaches with the transfer case. we're at one year now (bought it off rental with almost 35K miles) and haven't had any issues at all.
 
Can you describe or show where the filler plug is for the transfer case? Thanks
I need to know also, I'm at mazda service and they're telling me it's a "sealed" transfer case, can only fill,
no drain plug, 2013 awd
 
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I did the job on a weekend. The filler plug is next to the catalytic converter. It was very hard to reach and I asked my wife to help, her arm is twice smaller than mine. We couldn't suck the oil out so I just started to pump it in, I guess it was low. After a while the black oil came out of the filler plug. I continued to pump till the fresh came out. It is impossible to remove the old oil as the tube cannot go deep in the transfer case, so all you can do is mix it with new as much as you can and repeat the procedure couple times.
My wife was very unhappy to help me and said it was worse than cleaning the toilet :). She doesn't know that we will do it again and again :)
 
Hi, need some help from those who have been able to suck the fluid out. I got the drain plug out, but when I stuck my finger in the hole, I could feel that about half the opening was blocked by something inside the case. I then tried to insert a 5/16 tube in the opening, but it would only go in about 2 inches, and nothing could be sucked out. Do I just need to move the car a few inches? Thanks!
 
filler plug for CX-9 transfer case ?

I did the job on a weekend. The filler plug is next to the catalytic converter. It was very hard to reach and I asked my wife to help, her arm is twice smaller than mine. We couldn't suck the oil out so I just started to pump it in, I guess it was low. After a while the black oil came out of the filler plug. I continued to pump till the fresh came out. It is impossible to remove the old oil as the tube cannot go deep in the transfer case, so all you can do is mix it with new as much as you can and repeat the procedure couple times.
My wife was very unhappy to help me and said it was worse than cleaning the toilet :). She doesn't know that we will do it again and again :)



can someone please confirm this is the transfer case filler plug (green arrow) ?

CX-9 transfer case.jpg

I'm worried about the infamous transfer case failure and want to be proactive and perform regular fluid maintenance. So is everyone who is doing this maintenance using Red Line 75W140 fluid ?

also, does anyone know if the Mazda dealership perform a service to change the transfer case oil, from what I have read,

there's no way the transfer case oil should be treated as a lifetime fluid and it should be replaced regularly.

Thanks very much in advance.
 
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