Tires thumping (as if flat) during slow, tight turns

Hi all, We have a 2003 Subaru Legacy named Penny. Lately she’s been “thumping” when we make slow tight turns – usually when pulling into or out of a parking spot. This is less of a noise, more of a sensation. Thumping and bumping as if the front tires are flat, but that’s not the case. To complicate matters, it doesn’t seem to happen first thing in the morning. Starts showing up after a drive of 30 - 40 minutes and continues to get worse the longer we drive throughout the day. Driving straight is fine, less sharp turns also fine. Mechanic guessed axle and replaced both front axles last week. But the problem persists. We are independent musicians, traveling often, and NEED this car to drive reliably! Any ideas??

My first assumption was CV axles as well.

So my second is dry and binding ball joints or tie rod ends. Some of these can be (and should be) greased periodically. Do you know if the mechanic tried to lube them? Unfortunately, they can get dry and noisy and need replacement without any of the normal “external” signs (like too much play in them). So unfortunately there might be more guessing. I’d first ask about lubing them.

After that you’re probably onto strut bearings which can also bind and pop (they can sound a lot like bad CV axles). Someone should be able to figure that out by holding onto the spring while the wheel is turned. The noises will be associated with spring vibration.

Cigroller may well be correct, but I have a different theory.
I believe that the problem lies in the center viscous coupler.

If that turns out to be the case, it could be the result of a lot odometer miles (we don’t know the odometer mileage of your car), or–more likely–it is the result of running the car with mismatched tires.

Did you buy this as a new car, or as a used car? [If you bought it used, then unfortunately you probably wouldn’t know how it was driven & maintained by the previous owner(s)]

How long have you owned this car?

During your period of ownership…
…have you always had 4 tires that were the same size, the same brand, and had the same amount of tread wear on them?
…have the tires always been rotated on schedule?
…have you ever driven it for an extended period of time with a “donut” spare?

A yes answer to any of the above would explain excessive wear of the center viscous coupler.

Thanks guys. Car has 175,000. We are second owners. Bought 4 years ago. We’ve always had 4 matching tires. Not sure about previous. But we’ve put the past 90k miles on ourselves.

How often are the tires rotated?
Is the wear “even” from one tire to another?
What about use of the spare?

Tread separation is a possibility.

If the problem was the result of tread separation, don’t you think that the OP would be experiencing problems under various driving conditions in addition to making turns at very low speed?

I agree with CDCdriver on the center differential. But I’m not sure I would bother fixing it at this point. Possibly changing the center differential fluid/oil will help but I think at this time it is just an annoyance, so if you can live with it, drive on.

@vdcdriver, sorry, I slept through the turning part. Too many manhattans?

I’m with VDCdriver, this doesn’t sound like a tire thing. I like the center differential theory.