rear diff problem solved

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Mazda CX-9 GS AWD
I can validate this repair. Dealer wanted to replace the whole rear diff. for $$$$.
My local independent shop charged a few hours for the wire repair. I told them what the problem likely is so they didn't have to go searching.

Update Nov 2019:
Based on this video, I would expect my shop only fixed the wires external of the coupling the first time. They would not have completely disassembled the unit as shown here. The problem has now reappeared, and the wires have broken flush with the rubber grommet into the coupling. The same shop can't/won't fix it. At least not yet, until I show them the video ;) It's easy, right?
 
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V
2014 CX-9 Touring / 2008 Mazda 3 Touring 5-door
Great video! I might be able to use this for reference if I decide to tackle changing out the rear diff mounts myself. Do you think the rear diff mounts can be replaced without having to dissasemble to the drive shaft?
 
V
2019 CX-5 GT 184 2.2 twin turbodiesel auto - Sonic Silver
This sounds very patronising but I love it when someone with no mechanical skills has a go and fixes it themselves. I am a mechanic and I would always recommend doing so because as long as you don*t ruin it or hurt yourself, you*ve got nothing to lose!

All I would do differently is put all thefixing bolts in together and run them up evenly working opposite then 90 degrees etc until they are all up tight. It*s nit picking but it might save something getting twisted. Brilliant and I make quite a few videos and it takes quite a bit of work and time so again, thanks for all your effort.

PS, I reckon your helper *Bolt* was curled up in front of the fire while you were lay on that concrete floor ;-)
 
V
2014 CX-9 Touring AWD
Great video! I might be able to use this for reference if I decide to tackle changing out the rear diff mounts myself. Do you think the rear diff mounts can be replaced without having to dissasemble to the drive shaft?
Late reply, but hopefully, you were able to do the repair. You should have been able to replace the rear diff mounts without undoing the driveshaft.
 
V
2014 CX-9 Touring AWD
This sounds very patronising but I love it when someone with no mechanical skills has a go and fixes it themselves. I am a mechanic and I would always recommend doing so because as long as you don*t ruin it or hurt yourself, you*ve got nothing to lose!

All I would do differently is put all thefixing bolts in together and run them up evenly working opposite then 90 degrees etc until they are all up tight. It*s nit picking but it might save something getting twisted. Brilliant and I make quite a few videos and it takes quite a bit of work and time so again, thanks for all your effort.

PS, I reckon your helper *Bolt* was curled up in front of the fire while you were lay on that concrete floor ;-)
I'm here to learn, so next time, I will follow a more controlled bolt pattern when rebuilding, thank you!

And Bolt, was indeed, indoors by the fire.
 
V
Mazda CX-9 GS AWD
Great job! As usual, the first time is the hardest, but now armed with your video, everyone else can save a lot of time. The wires on mine have broken again, causing an intermittent 4WD light coming on. Based on Puma's information, I had a shop fix the wires a few years ago, but now they've gone again, but too deep inside the coupling to repair. Looks like I have to do this disassembly method next.

It appears from your third video, for reassembly, that you could let the diff pivot on the driveshafts and 'hang' down which would allow easy access to all the bolts and the wires. Is that the case? This would make fixing the wires only much easier, if you didn't have to remove the coupling.
Also your 'mistake' of not lining up the driveshaft and coupling holes is a huge relief to anyone else tackling the job. If you hadn't made it, someone else would've been cursing long and hard.


As I understand from the Ford Waterpump lawsuit there are millions of these engine/drivetrains out there. You would think that someone in the aftermarket would have come up with a remanufactured coupling that you could just swap out quickly. Or even just a wiring connector. I could see shop charging 2 hours labor for a quick swap out of the part.
Mandating replacement the whole diff for a $10 wire assembly is criminal.
 
V
Mazda CX-9 GS AWD
See Puma's photos above:

How is the solenoid affixed to the ring in the coupling? Is the whole assembly removable?
 
About the aftermarket solution for the diff wire, the thing is only us in northern places where there is salt have these problems, where they don't use salt on the roads the problem must not be there.

if you have a flashing awd, that is not it, the wire problem on the rear diff would lit a solid awd symbol. A flashing awd symbol for 10 seconds is a sign the awd system isn't working, so either transfer case or front diff teeth that are chewed up.
 
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V
Mazda CX-9 GS AWD
About the aftermarket solution for the diff wire, the thing is only us in northern places where there is salt have these problems, where they don't use salt on the roads the problem must not be there.

if you have a flashing awd, that is not it, the wire problem on the rear diff would lit a solid awd symbol. A flashing awd symbol for 10 seconds is a sign the awd system isn't working, so either transfer case or front diff teeth that are chewed up.

My light is on solid. The rear wheels don't drive when the front wheels spin in mud/snow. I've had all the problems. Broken transfer case (replaced 3x under Mazda extended warranty), the last time the transmission output shaft splines were sheared off.
It makes sense that only the northern/salty roads that cause the problem. But there must still be a few million of these units our there. Unless Ford ran the wire into the case in a different manner?
 
if the light is solid than yes it is the solenoid, you should be able to fix it.

what did you do for the sheared splines? How did they solved it? New Diff? That must have cost a lot of money!
 
V
Mazda CX-9 GS AWD
if the light is solid than yes it is the solenoid, you should be able to fix it.

what did you do for the sheared splines? How did they solved it? New Diff? That must have cost a lot of money!

I will try to take a look at it over the holidays if I can get access to a friends heated garage with a lift.

My dealer actually worked with me to get the transmission problem solved, surprisingly enough. Although it took a long time. At first they didn't believe my diagnosis of the sheared splines (based on the excellent information on this site). They even took the car to Mazda HQ.

In the end they had a local transmission shop source an output shaft from a used transmission and rebuilt mine. Or maybe I got the other used transmission, I can't be sure. The job cost me $2,000 which I was not pleased about, but better than having to buy a new transmission.
 
I will try to take a look at it over the holidays if I can get access to a friends heated garage with a lift.

My dealer actually worked with me to get the transmission problem solved, surprisingly enough. Although it took a long time. At first they didn't believe my diagnosis of the sheared splines (based on the excellent information on this site). They even took the car to Mazda HQ.

In the end they had a local transmission shop source an output shaft from a used transmission and rebuilt mine. Or maybe I got the other used transmission, I can't be sure. The job cost me $2,000 which I was not pleased about, but better than having to buy a new transmission.
damn 2000$ isn't a bad price considering the amount of work needed for such a job from a dealership.
 
i don't know how the inner parts work but it seems like it is just a magnet that connects the driveshaft to the rear diff when the magnet is engaged. Not sure what you mean by solenoid...
 

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