Slop in driveline

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SOLD 2002 Protege5; Current 2008 CX-9 Grand Touring
Hi, All.

My 2008 CX-9 GT AWD has a problem that is not uncommon, but I need your thoughts on the cause.

When I dip into the accelerator moderately aggressively after i coast for a second (not enough for the car to slow down), I often feel and hear a thump from the rear. It is almost as if the driveshaft connections had some play. Doesn't happen if I ease back on the accelerator.

Any thoughts on most likely culprits would be appreciated. If I can check myself, I will. If not, shop recommendations in Queens / Nassau County in NY would also be appreciated.

Thanks,
ZoomFive
 
Hi, All.

My 2008 CX-9 GT AWD has a problem that is not uncommon, but I need your thoughts on the cause.

When I dip into the accelerator moderately aggressively after i coast for a second (not enough for the car to slow down), I often feel and hear a thump from the rear. It is almost as if the driveshaft connections had some play. Doesn't happen if I ease back on the accelerator.

Any thoughts on most likely culprits would be appreciated. If I can check myself, I will. If not, shop recommendations in Queens / Nassau County in NY would also be appreciated.

Thanks,
ZoomFive



Could be transmission slippage. Could be differential backlash. The driveshaft is supposed to have a little rotational play at the differential but not tons. The drive axles should also have a slight amount of play - you have an AWD vehicle, no doubt. Yours is a 2008. Mine is a 2017. They both do the exact same thing. I've test driven multiple post-2016 CX-9s and confirm the same at low rpm/low throttle settings followed by moderate acceleration - like when approaching stop signs and then slowly moving through the intersection.

I guess, if you are hearing any whining associated with acceleration distinctly coming from underneath the vehicle then I'd be more concerned. I'd also be concerned if the "thump" turns into a "bump" from the rear. If you can put it on a rack and get under the vehicle, check for fluid leaks near the rear diff and where the drive shaft connects to it. Check the transmission case exterior for the same.
 
Could be transmission slippage. Could be differential backlash. The driveshaft is supposed to have a little rotational play at the differential but not tons. The drive axles should also have a slight amount of play - you have an AWD vehicle, no doubt. Yours is a 2008. Mine is a 2017. They both do the exact same thing. I've test driven multiple post-2016 CX-9s and confirm the same at low rpm/low throttle settings followed by moderate acceleration - like when approaching stop signs and then slowly moving through the intersection.

I guess, if you are hearing any whining associated with acceleration distinctly coming from underneath the vehicle then I'd be more concerned. I'd also be concerned if the "thump" turns into a "bump" from the rear. If you can put it on a rack and get under the vehicle, check for fluid leaks near the rear diff and where the drive shaft connects to it. Check the transmission case exterior for the same.


Hi Cessna CJ4.

Thanks for the reply. It is definitely a thump. So if I let off on the gas at a low enough speed (like 5-10 mph) and then step abruptly back on the gas. I will hear a thump and get a bump from the rear. At that point, the tranny hasn't downshifted.. I can repeat this consistently by doing what I described. Other than that, there's no real rear whining or noise. I think I saw some dark spot on the diff casing. Could a bad pinion seal or pinion bearing cause this? I wonder if there's a problem with my spider bearings?

ZoomFive
 
My wife's 2007 CX9 GT was exhibiting the same symptoms and upon inspection, the rear driveshaft support bearing/bushing was shot (rubber was broken) and the rubber mount on the passenger side of the rear differential near the snout had failed also. I replaced both and it fixed all the thumping when re-applying the throttle.
 
My wife's 2007 CX9 GT was exhibiting the same symptoms and upon inspection, the rear driveshaft support bearing/bushing was shot (rubber was broken) and the rubber mount on the passenger side of the rear differential near the snout had failed also. I replaced both and it fixed all the thumping when re-applying the throttle.

Thanks lincoln32v. I appreciate you weighing in. I'm glad you got it sorted and it wasn't anything more major. I have to go in for the airbag recall soon and may have the dealer look at it. Can you tell me ballpark on cost to address both of these?

Zoomfive
 
Thanks lincoln32v. I appreciate you weighing in. I'm glad you got it sorted and it wasn't anything more major. I have to go in for the airbag recall soon and may have the dealer look at it. Can you tell me ballpark on cost to address both of these?

Zoomfive

I purchased mine on ebay and installed myself
The diff. side mounts are around $150/ea. for the part only. You can buy just the bushing if you have access to a press for only $20/ea.

https://www.ebay.com (commissions earned)

https://www.ebay.com (commissions earned)

The downside do the driveshaft bushing is that you can buy just the bushing for around $30 but I couldn't find any info on how to separate the driveshaft sections. There are no bolts and it appears to be pressed together. Eventually, I gave in and just replaced the whole shaft from the dealer for $550! (boom04).

https://www.ebay.com (commissions earned)

https://www.jimellismazdaparts.com/products/gb/Mazda/CX-9/SHAFT--PROPELLER/1956224/KG0325100D9U.html?partner=googlebase_adwords&kwd=&origin=pla
 
I purchased mine on ebay and installed myself
The diff. side mounts are around $150/ea. for the part only. You can buy just the bushing if you have access to a press for only $20/ea.

https://www.ebay.com (commissions earned)

https://www.ebay.com (commissions earned)

The downside do the driveshaft bushing is that you can buy just the bushing for around $30 but I couldn't find any info on how to separate the driveshaft sections. There are no bolts and it appears to be pressed together. Eventually, I gave in and just replaced the whole shaft from the dealer for $550! (boom04).

https://www.ebay.com (commissions earned)

https://www.jimellismazdaparts.com/...ml?partner=googlebase_adwords&kwd=&origin=pla


Damn... the entire drive shaft?!? Did the drive new drive shaft have the support bushing / bearing attached?

-Zoomfive
 
Hi Cessna CJ4.

Thanks for the reply. It is definitely a thump. So if I let off on the gas at a low enough speed (like 5-10 mph) and then step abruptly back on the gas. I will hear a thump and get a bump from the rear. At that point, the tranny hasn't downshifted.. I can repeat this consistently by doing what I described. Other than that, there's no real rear whining or noise. I think I saw some dark spot on the diff casing. Could a bad pinion seal or pinion bearing cause this? I wonder if there's a problem with my spider bearings?

ZoomFive



Hey, ZoomFive. Checking back to see how this turned out for you. It has been a few months since you first reported the problem on this forum. Spider bearings, Pinion seal or Pinion bearing - all potential culprits based on your report. It looks like you have the 2007, so it does not have the newly designed extended range lock-up clutch inside the torque converter - the new one has a multi-disk clutch design and that's causing some issues in a handful of the newly designed CX-9s from what I read.

What was the end result for you?

My wife's 2007 CX9 GT was exhibiting the same symptoms and upon inspection, the rear driveshaft support bearing/bushing was shot (rubber was broken) and the rubber mount on the passenger side of the rear differential near the snout had failed also. I replaced both and it fixed all the thumping when re-applying the throttle.

Interesting.
 
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