Replaced Rear Wheel bearings now 4WD light is on all the time.

peakbagger

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2007 Mazda CX-9
We replaced the rear wheel bearings in my 2007 Mazda CX9 AWD. To make a 5 hour long story short, the wheel bearings didn't come out smoothly, and the new ones didn't fit on smoothly either. We had to use a lot of force to get those things on and off, and hammer had to be deployed occasionally.

Although the wheel bearing sound is gone, the 4WD light is on all the time and the TCS/DSC indicator (the slippery road sign) flashes on now and then. The ride seems uneven, like something is grabbing on one side and the brake power is reduced.

So..with the hammering of the axle, did we maybe damage the rear differential in some way? Or perhaps the brakes are on incorrectly? Would an incorrectly mounted brake cause that TCS/DCS light to come on? I haven't take the wheel off to look yet, it's just been too long of day, but I'll give it a look tomorrow.

Thanks!
 
There's a part called the reluctor (or tone) ring that you may have damaged. I'm pretty sure we have them front and rear on the CX9. if that got damaged or broken the sensor that reads the rear wheel speed will not function properly and cause all kinds of TCS and ABS warnings. On the other hand the ring could be fine and the sensor is damaged or simply not plugged in. If you find both the sensor and the reluctor ring and give them a visual inspection I hope the problem becomes readily apparent.
 
There's a part called the reluctor (or tone) ring that you may have damaged. I'm pretty sure we have them front and rear on the CX9. if that got damaged or broken the sensor that reads the rear wheel speed will not function properly and cause all kinds of TCS and ABS warnings. On the other hand the ring could be fine and the sensor is damaged or simply not plugged in. If you find both the sensor and the reluctor ring and give them a visual inspection I hope the problem becomes readily apparent.

Thanks! Something else I noticed is that accelerating from 1st to road speed, like 30 mph, the engine revs really high before switching to 4th gear. 4000 or more. Could that be caused by wheel speed sensor malfunction?
 
I cannot be sure about that shifting issue. However, if it new behavior after all that other work then it would not surprise me at all that it's related. When those sensors get conflicting signals all kinds of odd issues can occur. Hope it's an easy fix for you.
 
Could this cause a problem like that? A couple of the teeth look damaged. If that's the case, is it OK to drive? Will it send odd signals to the car to drive differently eventually killing my transfer case and or transmission?

<a href="https://imgur.com/F1xBhU1"><img src="https://i.imgur.com/F1xBhU1.jpg" title="source: imgur.com" /></a>
 
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I would say that that is enough to cause intermittent signals at the sensor. That part should be changed as soon as you can. As far as driving the vehicle I cannot be 100% sure but I do know of cases where folks drive their cars with broken reluctors with no ill effect. Again, not for an extended period of time though.
 
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