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Discussion Starter · #1 ·
To the 2020 Outback XT owners… for the past few months, every time i have to quickly accelerate into a turn, right or left, there is a serious “knocking” noise coming from the rear of the car. (My car has 18,000 miles.) I took the car to my local dealer and had the mechanic duplicate the problem on a road test. Their investigation pointed to the rear differential being the issue. They then tested a few other 2020 XT’s in their shop and found them to have the same problem. As of this posting (9/20), they still have my car but do not have a “fix” for it. They suggested that I not accelerate so fast… Since I live perpendicular to a very busy main road (no traffic light), I often have to accelerate quickly to get into moving traffic, so going slower isn’t always an option.

Are there any 2020 XT owners out there who have experienced this? Please post your experience, solutions, etc.

To those of you who have not experienced this issue, give it a test and post your post your findings… From a standstill position, quickly accelerate into a right or left turn.

As I continue to work with my dealer on this, I’ll post updates when anything significant developments.

Larry
 

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So, don't use the vehicle as intended? This is an offensive reply to a problem. Does your loaner do the same thing?
 

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2020 Onyx
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Thanks for bringing this to our attention!

Too bad there's not a video of the sound - is there any way to describe it in more detail? When you say it's serious, does that mean loud?

With so many words available - is it slightly like a clunk, click, clack, tick-tick, and is it just a single sharp sound or is it tat-tat-tat-tat like a slipping gear?

The torque vectoring/stabilty control I imagine would intervene on a near 90 degree full throttle turn - need more detailed info to confirm and replicate this issue.

Just to add that if there is a differential having a problem it's more likely to be the center differential than the rear diff.
 
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Discussion Starter · #4 ·
Arf193... My loaner is a 2021 Forrester, and no, it doesn't do it...

SilverOnyx... It's a bit loud, definitely audible. It's more like a rapid clunking sound. It lasts a few seconds into the turn; longer if it's a wider, longer turn. And, yes, these are 90 degree, close to full throttle and full throttle turns.

And, the dealer hasn't really committed, at least to me, to what the problem is exactly. It's all, I guess, in the discussion stage at the moment...
 

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2020 Onyx
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Here's a thread from the Ascent forum - for a different issue but also about turning and accelerating - just providing context that there can be more than one issue accelerating and turning.

 
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I have a similar noise, it's about half my left turns only and I get 1 or 2 light knocks while turning.

I had a CV joint fail under warranty on my Crosstrek and it sounded similar. The difference with that was I could recreate and it would happen when reversing and turning also.

Do you have the Subaru rear diff cover? I do, I wonder if it is impacting somehow when under a turning load?
 

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Discussion Starter · #8 ·
SilverOnyx: Interesting because for the first 2 months or so with this issue, I only noticed it when the car was cold - first drive of the day.

SlapHappy: I gotta believe that the service dept. mechanics checked all that out...

Peep: Ditto to Slaphappy.
 

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SilverOnyx: Interesting because for the first 2 months or so with this issue, I only noticed it when the car was cold - first drive of the day.

SlapHappy: I gotta believe that the service dept. mechanics checked all that out...

Peep: Ditto to Slaphappy.
If its simple it was probably over looked.
I am just a KISS kinda guy. I had something banging around in the back of my Outback. Drove me nuts. Crawled under the car thinking it was the rear diff breaking loose or the drive shaft u-joint coming apart. Nope it was foam with car changing tools bounding around. This noise was all the freaking time. Small bumps, turns braking. Took it to the dealership and they couldn't find the issue. Had the wife drive while I sat in the back seat with half the back seat laid down. I eventually figured it out. Dealerships do their best but you know your vehicle the best.
I hope its something simple like loose foam.
 

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To the 2020 Outback XT owners… for the past few months, every time i have to quickly accelerate into a turn, right or left, there is a serious “knocking” noise coming from the rear of the car. (My car has 18,000 miles.) I took the car to my local dealer and had the mechanic duplicate the problem on a road test. Their investigation pointed to the rear differential being the issue. They then tested a few other 2020 XT’s in their shop and found them to have the same problem. As of this posting (9/20), they still have my car but do not have a “fix” for it. They suggested that I not accelerate so fast… Since I live perpendicular to a very busy main road (no traffic light), I often have to accelerate quickly to get into moving traffic, so going slower isn’t always an option.

Are there any 2020 XT owners out there who have experienced this? Please post your experience, solutions, etc.

To those of you who have not experienced this issue, give it a test and post your post your findings… From a standstill position, quickly accelerate into a right or left turn.

As I continue to work with my dealer on this, I’ll post updates when anything significant developments.

Larry
I just took my 2020xt for the exact same problem. As of right now, the dealer has ordered a new transmission. We'll see if that fixes the problem or if they need to look at the differential as well.
 

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I just took my 2020xt for the exact same problem. As of right now, the dealer has ordered a new transmission. We'll see if that fixes the problem or if they need to look at the differential as well.
 

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Discussion Starter · #13 ·
Dunevant... Definitely let me know if it does! My dealer had my car for two months. They replaced a bunch of parts (shafts, ball bearings, seals, clutch plates, etc.) and it still does the exact same thing! I've been in contact with one of Subaru America's tech guys who has been monitoring the repairs and I just informed him that I still have the problem; whatever they did to it did not fix it and that I'm gonna live with it unless it gets worse. Note that I polled some 8-10 XT owners on this site to see how many had the same issue, and none said they did. You're the first. So, if the new transmission solves it, I'll need to know. Good luck!
 

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I had the same problem on my 2020 XT and also shuddering.
I had a rebuild of the rear differential and the transfer clutch. I wish they did the whole transmission, but that did not happen. My gas milehas dropped significantly, but I am guessing that is because I actually have all wheel drive again. My noise is gone but I need to give it some time to see if it is fixed. I think I may be over sensitive now, so I will have my wife drive it. At 28,000 miles it does not build confidence. Good luck!
 

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Discussion Starter · #15 ·
Yes, keep me posted, keep all of us posted. what is the mileage you’re getting? I’m curious. I’ve been getting about 27 mpg where I live - sort of like the outer edge of suburbia.
 

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Yes, keep me posted, keep all of us posted. what is the mileage you’re getting? I’m curious. I’ve been getting about 27 mpg where I live - sort of like the outer edge of suburbia.
I was getting around 26 mpg and I live outside the city and my drive is pretty straight 55 mph. I reset after the repair a couple of times and now I am getting 21-22 mpg. They did not give me any breakin instructions but the post from the Ascent forum said there should be one. I am hoping the gas mileage improves. Honestly going through all this and trying to prove the problem with service and SOA has been a bad experience for first time Subaru ownership. The car is perfect for what I need, but once new cars are back to normal stock, I will probably trade out before the warranty goes out on the power train. From the forum it seems like my problem is a rare occurrence, but when it happens to you it does not seem so rare. Hopefully these problems are new model woes and not a systemic problem. Best of luck.
 

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Discussion Starter · #17 ·
It doesn’t sound kosher to me that your mileage should decrease that much; but I am not and never was, a mechanic. All the more reason for me to leave well enough alone.

This is my third Subaru, and I do love them especially this XT. On the past three occasions that I went looking to buy a new car, for the money, the Subaru always beat out the other contenders. I test drove Acuras, Toyotas, Volkswagens, Hondas, etc. even the Lexus. Bang for the buck, they didn’t beat the Subaru. As far as their service, this is the first time I’ve had any sort of problem with them where they couldn’t deal properly with the issue.

As far as things getting back to normal, I don’t see it happening for a while, at least a year. Used cars are also in short supply. Cars two and three years old are being sold for the price they were when they were new. It’s crazy. You will need to get to the bottom of your gas mileage issue because you’re going to have that car for a while.
 

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I'm hoping that his rear differential needs to be broken in if that's something they changed. It might have too tight a lash. If I were him I'd change the differential fluid after 1000 miles and see if it's full of metal paste.
 
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