Sound due to tire rotation or another problem?


#1

I just had my tires rotated on my Subaru Outback wagon (automatic transmission). Since then, I have noticed that the car acts like it is in a lower gear when it is not. For example, when I take my foot off the accelerator, the car seems to slow down faster than it did before and sort of grinds and whines a bit (almost like it does when you’re driving in 3rd or 2nd gear and the engine itself acts as a brake, except I am in normal drive). I am HOPING this is normal due to the tire rotation and will go away after I drive on it for a while and the tires get worn a bit. Note that the car does not shimmy or shake at all, so I don’t think it’s a tire rebalance issue, but a tire tread issue. Does this logic make sense, or should I be more concerned about something else?


#2

Tire rotation would absolutely not cause this.

What is the tachometer doing during all this? Are you sure the car is actually shifting into top gear? Have you accidentally disengaged overdrive?


#3

rotate them back. see if the problem goes away. i would actually rotate them soon, in the off chance this is causing a problem with your transmission.


#4

You didn’t tell us some vital bits of information, such as the model year of your Subaru, the odometer mileage, and how often you rotate your tires. Whether you rotate them at Subaru’s recommended 7,500 mile interval or at another interval, the important thing is to consistently rotate them at the same interval–preferably somewhere between 5k and 7.5 k.

If they have not been rotated at a consistent interval, there could be uneven wear on those tires. If there is extremely uneven wear on your tires at this point, it is possible that some damage to the center differential could have resulted, and that could have something to do with the situation that you are currently experiencing.


#5

My RPMs are not doing anything unusual from what I can tell - when I hit the accelerator, it accelerates normally and turns over into the appropriate gear without issue. I can get on the highway and don’t notice any difference in the car’s performance relative to what I did before the tire rotation took place. I only notice sound and slow down in the car when I take my foot off the accelerator after going maybe 30MPH and letting the car come to a slower speed on its own (without tapping the brakes). I do not believe there is overdrive on this model - Subaru Outback wagon 2004.


#6

Model year is 2004, odometer reads around 43000 miles or so, and the car has been serviced almost solely at a dealership, so I believe the tires have been rotated before, though I will go back and look to see how many times. I don’t think they’ve been rotated at the level of frequency you suggest.


#7

If you look at the manufacturer’s maintenance schedule, you will see that it specifies 7,500 mile rotation intervals for the tires. Because even tread wear is critically important on AWD vehicles, it is really vital to adhere to this type of recommendation. (In other words, the manufacturer didn’t go to the bother to list this procedure just to use ink and paper.)

Of course, if you wanted to rotate them every 5k, that would be fine also. However, going for longer mileage intervals is likely to produce the type of uneven tread wear that can cause problems with the center differential.

I sincerely hope that I am wrong, as replacing the center differential is not a cheap repair.

Addendum: 43k would be unusually early for a center differential to be replaced, but anything is possible if the car had tires of varying tread depth on it. By any chance–did you ever have a tire problem that resulted in buying just one tire? I ask this because that is a classic cause of center differential failure, and any tire shop that is genuinely knowledgeable will advise you of this.


#8

no, these are the original tires on the car. No one-off tire replacements to-date…


#9

looks like my check engine light turned on today, so that’s a little disconcerting. I will be bringing the car back to the shop tomorrow…


#10

In case anyone is interested to know the outcome here, the dealership told me the catalytic converter needed to be replaced. Apparently the tire rotation was coincidental. We’ll see. Luckily, the converter is under warranty, so it costs me nothing but time to determine if this is indeed the problem. Anyway, thanks for all of your input.