Why is my 2011 Outback intermittently squeaking at 60-65 mph?

Question

I have a 2011 Subaru Outback. It has 175k miles and a CVT transmission. I’ve had a lot of work done on it this summer:

• serpentine belt replaced
• Front driver’s side wheel bearing replaced
• Windshield wiper motor replaced due to recall
• Rear brake rotors replaced
• Both O2 sensors replaced

The car drives like a dream BUT there is now an intermittent squeak. I’ve taken it to the mechanic twice and they can’t reproduce or find anything wrong. Up until this morning, the squeak might happen once a week but I‘ve driven three hundred miles without it happening at all. Today it happened 4-5 times in a ten mile journey.

It sounds like a tire squeal. It seems like it may be coming from the center, possibly under the hood. It sounds the same whether you’re in the passenger seat or driver seat.

Before the squeak happens, the engine note changes and the RPM dial goes up by four or five hundred - but I’m not accelerating and the speed stays steady. The rpm drops back down right after the noise. When the squeak happens, the gas pedal depresses under your foot like a spring is loosening. Right on the squeak, you feel a loss of power and the movement of the car changes, sometimes like a lurch. It’s quick.

90% of the occurrences have been when going 60-65 mph, gas steady.

There was no heat or AC on when it squeaked 4-5 times this morning. The AC doesn’t seem to cut out when it happens.

Other observations which may not be accurate.

• May happen more often in the morning.
• May happen more often on new pavement.
• May be a correlation between accelerating and the squeak happening a minute later.

Any ideas?

Update: My mechanic referred me to a transmission specialist. They can't reproduce it either. It is an unusual way for a transmission to start failing, if that is in fact what is happening. There are no codes, fluid looks good, no leaks. If it's not the transmission, it could be the ECM.

Also, here is the sound: https://soundcloud.com/user-827337134/new-recording-7

Answer 1

After seeing this video (not mine) of the squeal and dashboard, a Subaru specialist diagnosed the problem as a worn bearing in the Torque Converter Clutch (TCC). This is a known issue with this generation of Outbacks and was one reason for the recall on the CVT transmissions a few years ago.

They said I could continue to drive the car without damaging it. A key symptom of a failed TCC is the car stalls at stop signs. I did not have that problem but decided to swap out the part ($1400 incl. labor).

The squeak was even worse when I got the car back. I put 800 miles on the car before the mechanic swapped the part out again. The car continued to squeak for the first 200 miles. They flashed the ECU ROM again and I have not had an incident in the past 750 miles. I need to put another 1-2k miles on the car before I am confident in this fix.

In hindsight, I would wait for the car to stall at stops before replacing the TCC. My fear was that I would be stranded far from home due to sudden transmission failure, but I put many miles on this car while it was squeaking. I talked with another person who put 30k miles on their car and never diagnosed or repaired the problem. Two different mechanics told me that driving would not cause more damage.

If it is not the TCC, there is a good chance it is a failed solenoid in the valve body. The valve body part costs $800 but the solenoid causing the problem may be available for $120. This problem usually throws a code at some point and does not fail silently like the TCC. The mechanic told me I might see the transmission light on the dash blink quickly if this were the cause.

If it is not either of those, it could be a CVT pulley. If that were the issue, you would eventually see metal in the transmission fluid and it would eventually throw a code when the fluid got bad enough. This would be a worst case scenario as continued driving would damage the car.

I learned some of what I posted here through discussions on the Subaru Outback forums.

2022 update My car now has 198k miles. It stopped squeaking after flashing the ECU but I still noticed a couple occasional RPM jumps (which could be due to hypersensitivity). Two weeks ago the Christmas lights came on, this time with a flashing AT Oil Engine light. It threw P2763 and P2762 codes. The problem was identified as a failed valve body solenoid.

It's possible this was the culprit all along so I am more firmly convinced that it is important to wait for the car to start stalling before replacing the TCC. Now I'm just waiting for the CVT pulley to go!

2022 Update Part 2: A month later and now I'm back to the squeal and RPM jump again. I have zero confidence in the car. In hindsight, I wish I had replaced it in 2019 rather than spending thousands on transmission repairs.