rear diff problem solved

Just wanted to share in case it happens to someone else, i got the 4wd light in my dash and it wouldn't go away. Rear wheels wouldn't work either so it was a real code. Got the code which is p1887 awd control solenoid circuit failure. Well that "solenoid" is basically the magnet that engages the rear diff when needed and it costs upward of 1k$ in part alone. I decided to check what was wrong with it hoping it was just an unplugged connector but it was not. What i found though is the wire entering the diff housing that was full of that green stuff (sorry don't know the English name, we call it vert de gris) and one of the wire was about to cut itself. So i had to remove the complete housing to see what could be done and realise that i could remove the rubber in which the wires enter. I then welded some new wire and made the holes bigger in the rubber and put everything back together and now works like a charm. Saved me a heck a lot of money, if i had been to the dealer, i am sure they would have changed the whole part.

So for those who live in Canada where they put a lot of salt on the road in winter, check this out during the next ol change and see if it is about to rip apart. Here is the only picture i took, it was once the repair was almost over

 
that's awesome! a solenoid is like you say, just an electrical magnet. the green stuff is corrosion or oxidation on the copper wires (if I understand your description correctly) so that tripped the code.
I love reading about repairs like this, thanks!
 
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2012 CX-9 Sport AWD Stormy Blue, 2008 Mazda3i Manual
Well, I have just a tad over 12K miles on mine and less that two years of age. Yesterday morning after noticing burning oil smell after driving I saw oily fluid dripping between the rear wheels, right from where the exhaust pipe splits in two. The car had been sitting in a blizzard outside overnight and there was a lot of snow blown under the vehicle if that is of any significance. The nearest Mazda dealer, from which we bought the car new, is 75 miles away, so depending on what they say I am either driving a leaking car over there or they are sending a tow truck...
 
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2012 CX-9 Sport AWD Stormy Blue, 2008 Mazda3i Manual
Update: the car was fine to drive to the dealer. The dealer found that something was clogged somewhere in or near the rear differential and cleaned whatever needed to be cleaned. There was no charge, but they did open an inquiry with Mazda as to whether anything else needs to be done. Supposedly the car is good to go, at least for now.
 
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2012 CX-9 Sport AWD Stormy Blue, 2008 Mazda3i Manual
Update#2: the leaking continues. Credit to the dealer, they had proactively contacted me on the phone about Mazda requesting to replace some part before I actually noticed the leak myself. I will be taking her in again in a couple of weeks once I have the time to do so. Fortunately, I have another car to drive in the meantime.
 
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2012 CX-9 Sport AWD Stormy Blue, 2008 Mazda3i Manual
Update #3. After two weeks at the shop, the dealer replaced the rear differential, seals and whole host of other items. I was given a rental for this time. Cost out of pocket 0.
I brought the car home yesterday and - guess what - it is dripping oil between rear wheels. I wonder if this is because of some excess oil accumulated somewhere or the car still not fixed properly. I will give the dealer a call to find out.
 
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2012 CX-9 Sport AWD Stormy Blue, 2008 Mazda3i Manual
Update #4. The "leaking" oil is clear in color, not copper, so the tech has advised over the phone that this is likely the excess grease that they used to lubricate the parts after the replacement, which they confirmed should be clear in color. The differential fluid should be copper in color. So it looks like the car is fixed for now.
 
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2012 CX-9 Sport AWD Stormy Blue, 2008 Mazda3i Manual
Update #5. The leaking continued. A local mechanic looked at it and determined that it is indeed differential oil that is continuing to leak. It turns out that the advisor on the phone was incorrect about the color of the fluid: differential oil is grey, not copper. The leak is severe enough that the car can not be driven safely and so it will be towed to the dealer.
 
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2012 CX-9 Sport AWD Stormy Blue, 2008 Mazda3i Manual
Update #6. The dealer confirmed the leak. They replaced the seals again and did some other things. The car seems to be fixed, at least for now. At a first glance there is at least no lingering burnt oil smell in the garage.
 
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2012 CX-9 Sport AWD Stormy Blue, 2008 Mazda3i Manual
sts7049 I have no complaints about the dealer service. I am hoping this was just a fluke and the car will resume being good because I like the way the car drives and I would like to keep it for a while.
 
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2011 CX-9 GS
Just wanted to share in case it happens to someone else, i got the 4wd light in my dash and it wouldn't go away. Rear wheels wouldn't work either so it was a real code. Got the code which is p1887 awd control solenoid circuit failure. Well that "solenoid" is basically the magnet that engages the rear diff when needed and it costs upward of 1k$ in part alone. I decided to check what was wrong with it hoping it was just an unplugged connector but it was not. What i found though is the wire entering the diff housing that was full of that green stuff (sorry don't know the English name, we call it vert de gris) and one of the wire was about to cut itself. So i had to remove the complete housing to see what could be done and realise that i could remove the rubber in which the wires enter. I then welded some new wire and made the holes bigger in the rubber and put everything back together and now works like a charm. Saved me a heck a lot of money, if i had been to the dealer, i am sure they would have changed the whole part.

So for those who live in Canada where they put a lot of salt on the road in winter, check this out during the next ol change and see if it is about to rip apart. Here is the only picture i took, it was once the repair was almost over

I have the same problem. Very helpful post. Thanks Puma!
 
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2014 CX-9 Touring AWD
Puma! Thank you so much for sharing this. Same problem here! The dealership wants 3k to replace it, and a transmission shop quoted me 1k. I have a few questions:

1. Did you have to remove the entire transfer case, or just the coupling?

2. Is there a specialized seal between the two that I'll have to order?

3. Can I do this in my home garage, or do I need more tools/expertise?

I really appreciate the help you've given, and any more you may be able to give.

Thanks!
 
you are taking about transfer case, just want to make sure you problem really is the rear diff and not the transfer case that is in the middle of the vehicule.

you only remove the front portion from what i can remember. there is no special seal, i used "the right stuff" silicone gasket maker. It can be done in a home garage if you are pretty mechanically inclined. i have a lift in my garage so it was easier.
 
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2014 CX-9 Touring AWD
Thank you so much for the information, and the quick reply!

It is definitely the rear diff, but thank you for the clarification.

I am considering taking the day off tomorrow to repair the AWD, but I just want to make sure I have an understanding of the task before I have to have a mechanic make a house-call!!!

So here is my plan:


1. Ramp and support rear wheels.
2. Disconnect any remaining wires from rear diff
3. Disconnect driveshaft and supports
4. Drain rear diff
5. Remove front portion of rear diff
6. Solder new wires into terminals
7. Increase gauge of gasket and thread new wire through
8. Clean seal ring
9. Apply sealant and replace front portion of diff
10. Refill diff fluid
11. Reattach driveshaft
12. Connect wires to harness
13. Post successful video to YouTube! (haha)


Does this sound about right?

Again, I cannot thank you enough for the knowledge!
 
yeah it does, i beleive you have to disconnect some exhaust pieces in order to remove the driveshaft but i am not sure, you will see once you get there.
 
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2014 CX-9 Touring AWD
yeah it does, i beleive you have to disconnect some exhaust pieces in order to remove the driveshaft but i am not sure, you will see once you get there.
Ok. A few weeks delayed, but I am now in the middle of the repair. I have removed all the pieces, but I cant figure out how to separate the coupling unit from the rear differential without destroying the aluminum.

How did you get through the rtv gasket?

Does the coupling unit spin out or just pull out?

Thank you!!
 
man i can't remember but it just pulls out i beleive once you removed all the bolts from what i can remember
 
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