- :
- Canada
I'm posting this to vent, but also to inform.
Back in January, I noticed that the car started making loud clunking noises. They were coming from the rear and seemed to be intermittent at first, but I soon realized that I could only hear the sound when the traction control light turned on and AWD was supposed to engage. I contacted my dealership to book a diagnosis appointment, but they seemed very skeptical that this was an AWD issue and assured me that if there was an issue with the rear diff or the AWD system, I'd have a warning light on the dash (there are no warnings or lights, and no codes stored). They basically refused to schedule an appointment because they were not confident they could diagnose the intermittent noise and just wrote off my concerns about a possible rear diff failure. I contacted them a few times and also spoke with an independent mechanic, who said the same thing about codes and warning lights appearing if there was an issue with the AWD system.
In August, I did a transfer case and rear diff drain and fill myself to confirm my assumptions. The transfer case fluid looked good, but the rear diff fluid came out silver/gray, and I was able to use a pick to pull a bunch of metal chunks out of the drain hole.
I've tried to get assistance from my dealer, which I knew I wouldn't be much help as I do all my service myself and because my car's powertrain warranty lapsed in 2023. I've had issues reaching Mazda Canada via phone because both numbers that are available (Regional Office and Mazda Customer Relations) will either ring with no answer, or I'd get a message that said to call back later. It didn't seem to matter when I called, I could never get through to anyone. I finally sent my complaint through the "Contact Us" form on the website and someone eventually got back to me. I was hoping to reason with them to get some form of goodwill assistance, but it's not looking good. Bad luck I guess. They are denying that there is a manufacturer defect because if there was, I would have had issues well before the warranty expired. However, if there is no defect, and if there is no fluid change interval for the rear diff as they have posted in the manual, the differential is expected to last much longer.
The whole point of this is to let you all know that if your rear diff is failing, there is a good chance that you will not have any warning lights. This is a major safety issue as the car will behave unpredictably in low traction situations. The car thinks there is nothing wrong with the AWD system, so the traction control is less effective and the car will not "assist" when it should because it thinks AWD is active. It's basically worse than a FWD car with no traction control system now. Further, because there are no warning lights, drivers will not know that there is an issue to investigate. If I had a warning light, and if the dealership was better informed, I would have changed my rear diff fluid much earlier, and I may have been able to avoid a complete loss of AWD.
I don't know if a "late" fluid change is to blame here. When I drained the fluid into a bottle, I left it to settle, and when all the metal was at the bottom, I could see that the fluid looked just like the front transfer case's fluid. It's possible that the fluid was underfilled at the factory, as I had drained about 10oz of fluid with the metal bits included. All this to say, change your fluids. The manual doesn't specify an interval, and if you ask them, they will tell you it's a lifetime fluid - this is a lie. Change your fluid at 30k or 40k mi intervals. Save yourself the headaches I'm dealing with now.
At this point in the process, I will likely have to proceed to opening a case with CAMVAP. I just sent off one last email, so I guess we'll see. But it looks like this may be my first and last new Mazda. I can't support buying new from them if this is the kind of support I can expect. I know I'm out of warranty, but it doesn't change the fact that this component failed early and left me with an unsafe, unpredictable vehicle.
Anyone else who's had their rear diff replaced or serviced, what did it cost you? Did you go through the dealership or an independent shop?
AWD not working
Rear diff drain
Back in January, I noticed that the car started making loud clunking noises. They were coming from the rear and seemed to be intermittent at first, but I soon realized that I could only hear the sound when the traction control light turned on and AWD was supposed to engage. I contacted my dealership to book a diagnosis appointment, but they seemed very skeptical that this was an AWD issue and assured me that if there was an issue with the rear diff or the AWD system, I'd have a warning light on the dash (there are no warnings or lights, and no codes stored). They basically refused to schedule an appointment because they were not confident they could diagnose the intermittent noise and just wrote off my concerns about a possible rear diff failure. I contacted them a few times and also spoke with an independent mechanic, who said the same thing about codes and warning lights appearing if there was an issue with the AWD system.
In August, I did a transfer case and rear diff drain and fill myself to confirm my assumptions. The transfer case fluid looked good, but the rear diff fluid came out silver/gray, and I was able to use a pick to pull a bunch of metal chunks out of the drain hole.
I've tried to get assistance from my dealer, which I knew I wouldn't be much help as I do all my service myself and because my car's powertrain warranty lapsed in 2023. I've had issues reaching Mazda Canada via phone because both numbers that are available (Regional Office and Mazda Customer Relations) will either ring with no answer, or I'd get a message that said to call back later. It didn't seem to matter when I called, I could never get through to anyone. I finally sent my complaint through the "Contact Us" form on the website and someone eventually got back to me. I was hoping to reason with them to get some form of goodwill assistance, but it's not looking good. Bad luck I guess. They are denying that there is a manufacturer defect because if there was, I would have had issues well before the warranty expired. However, if there is no defect, and if there is no fluid change interval for the rear diff as they have posted in the manual, the differential is expected to last much longer.
The whole point of this is to let you all know that if your rear diff is failing, there is a good chance that you will not have any warning lights. This is a major safety issue as the car will behave unpredictably in low traction situations. The car thinks there is nothing wrong with the AWD system, so the traction control is less effective and the car will not "assist" when it should because it thinks AWD is active. It's basically worse than a FWD car with no traction control system now. Further, because there are no warning lights, drivers will not know that there is an issue to investigate. If I had a warning light, and if the dealership was better informed, I would have changed my rear diff fluid much earlier, and I may have been able to avoid a complete loss of AWD.
I don't know if a "late" fluid change is to blame here. When I drained the fluid into a bottle, I left it to settle, and when all the metal was at the bottom, I could see that the fluid looked just like the front transfer case's fluid. It's possible that the fluid was underfilled at the factory, as I had drained about 10oz of fluid with the metal bits included. All this to say, change your fluids. The manual doesn't specify an interval, and if you ask them, they will tell you it's a lifetime fluid - this is a lie. Change your fluid at 30k or 40k mi intervals. Save yourself the headaches I'm dealing with now.
At this point in the process, I will likely have to proceed to opening a case with CAMVAP. I just sent off one last email, so I guess we'll see. But it looks like this may be my first and last new Mazda. I can't support buying new from them if this is the kind of support I can expect. I know I'm out of warranty, but it doesn't change the fact that this component failed early and left me with an unsafe, unpredictable vehicle.
Anyone else who's had their rear diff replaced or serviced, what did it cost you? Did you go through the dealership or an independent shop?
AWD not working
Rear diff drain
