2015 CX5 2.5 AWD Transmission took a dump

Chris_Top_Her

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San Antonio, Texas
:
'15 CX-5 Miata AWD
On Thursday the aug 24 I was leaving a taco joint. As I pulled out the parking lot onto the street and revved, I heard a "whir" and then clunking. I immediately let off the gas and parked nearby. I was certain I had spun a rod bearing. I dumped about a half qt of oil I had in the boot into the engine. I was about 1 mile from home so I slowly drove it there. The following morning I picked up a rental and ordered some rod end bearing from the dealership. I figured since I noticed it as soon as it happened, I may be able to rescue the motor. I picked up the part on Saturday. Being in Texas with the hurricane and all, I waited until Sunday for maybe better weather, which didn't happen.

Sunday I go ahead and work on the car so that I could handle business during the week. I removed the oil filter, oil pan (including having to drill out a stuck bolt which took about 20 minutes on its own), the balance shaft and then the oil pump, followed by the rod end caps, accessing them by moving the crankshaft as needed. To my surprise (and relief) none of the bearing I removed showed any signs of abnormal wear, nor did I see any metal anywhere. I went ahead and replaced all of the bearing with standard size, torqued the caps back on to spec, plus the 80-100* turn , aligned the timing chain, balance shaft and oil pump sprockets as specified and reinstalled everything. As long as I didn't **** something up there I just renewed my engine a bit, if I did, well I guess I'll find out lol.

So after about 5 changed of clothes and 4 pairs of soaked shoes, and some time for the RTV to cure, I fill up with 5w30 I start the engine. So far I'd spent about 6 hours on this repair. I let it idle for about 20 minutes; everything sounds good. I cut it off, remove the jacks etc and start it again. I rev the engine a few times, no knocking; all seems good! I put the car into gear and move it, and the same knocking is back. ****, I guess I have a scored crankshaft, new engine time. So I begin to make preparations to buy a new engine and labour to install it.

In the meantime I'd put some lucas synthetic into the motor, and had been moving it back and forth in the parking spot. I noticed that in addition to knocking while only in motion, it was always constant and increased with speed. I realized I could get the car rolling, put the car in neutral, rev the engine and the knocking frequency did not change. I realized it was most likely the trans at this point. I put the car up on jacks, removed the DSC 30 and then 50 amp to test FWD/AWD clunking, which it did on both. Finally I put the car on jacks and (with DSC ABS 50 out) did some testing to confirm the clunking was based on movement of the driveline and not the motor. I isolated the noise to the transaxle, directly under the ATF pan. The ATF does not appear burnt nor is it at an improper level.

My car is out of warranty, but I'm going to contact mazda to see what the are willing to do considering the problems with other copies of this transmission. If anything, at least a transaxle is cheaper to buy and install than a new/used motor.

Here is a video of my problem. Noticed the RPM/gear indicators compared to the clunk sound.

 
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yrwei52

2016 Mazda CX-5 GT AWD w/Tech Pkg
Contributor
:
Plano, Texas, USA
Hurricane Harvey making landfall in Texas as Category 4 and your transmission fell as another victim from it ⋯

Sorry to hear your transmission problem after you've spent 5 hours under the bad weather replacing the connecting rod bearings for the wrong reason. It's weird to have that kind of clunking noise from the transmission. How many miles does the transmission have? Hope you can get some help from Mazda North American Operations somehow. And I didn't aware replacing transmission with a used one is cheaper then a (used) engine swap.
 

piotrek91

Member
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2013 CX-5 6MT
I'm really genuinely sorry to read that you're having transmission problems. Hopefully you'll be able to get it fixed and back on the road without too much more hassle.

but.. holy s*** this is a really funny post.
I'm very impressed by how much your eagerness to take things apart and your mechanical ability outpaced your ability to diagnose what was wrong.

Also, you should consider getting an AWD manual transmission shipped from Europe.
 
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2016.5 GT AWD
It happens. Sometimes you just KNOW it's A after you diagnose the problem. Then it turns out to be B. Then it's obvious what that little voice way in the background was trying to say. Experience is what you get when you don't get what you want.
 

Chris_Top_Her

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San Antonio, Texas
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'15 CX-5 Miata AWD
Next time you might want to use a stethoscope to help you pin point noises before you rip everything apart. Might save you a lot of time and money. https://www.amazon.com/dp/B0015DLMOO/?tag=m20b7-20
I'm going to get one soon. The testing I did afterwards to figure out it was the trans would have damaged the engine further if it was indeed a spun rod bearing. If anything the teardown made it safe to do other testing to find out the problem.
 

Chris_Top_Her

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San Antonio, Texas
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'15 CX-5 Miata AWD
It happens. Sometimes you just KNOW it's A after you diagnose the problem. Then it turns out to be B. Then it's obvious what that little voice way in the background was trying to say. Experience is what you get when you don't get what you want.

I've learned how to save a possibly dying engine (or refresh a very worn one) from bad rod bearings at least, haha
 
Let me get this straight...You tore the bottom end down in the rain, did what you had to do to fix what you thought the issue was and it still made the noise afterwards? I would have killed it w/dynamite after all of that.
I commend you!
 

tibimakai

San Dimas CA
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USA
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2014 CX-5 Touring
I agree with piotrek91.
You should make a diy, on how to change crankshaft bearings.
At least that much would come out, from those hard hours of work.
 

Chris_Top_Her

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San Antonio, Texas
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'15 CX-5 Miata AWD
I agree with piotrek91.
You should make a diy, on how to change crankshaft bearings.
At least that much would come out, from those hard hours of work.

Had it not been pouring, I would have recorded :/
 
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2016.5 Mazda CX 5 Grand Touring W/ Tech PKG
I sure hope Mazda covers this as it's a known issue.... heck tell them about this forum and how active you and we are, maybe they'll work it in under a warranty.

Good luck...
Thanks for the video..
 

GJ-Molestor

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2011 BMW 528i, 2015 Mazda 6, 1995 Nissan Maxima Manual
how did you drive the car for the first couple thousand miles of its life?
 

Chris_Top_Her

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San Antonio, Texas
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'15 CX-5 Miata AWD
Coolant was changed when engine was replaced, not sure of condition but it had been drain and filled at least once prior
 

Chris_Top_Her

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San Antonio, Texas
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'15 CX-5 Miata AWD
Just ordered a 2014 20k trans 742 shipped. About an hr north of the shop. Gonna call mazda about it but if they don't want to do anything with it I'll dismantle it for learning and to see what is obviously broke. Or I may try to sell it on the tuning pages for guys who might wanna convert their 3 to awd.