Just purchased a 90,000 mile '03 S60 AWD geartronic trans. Live at 5000' elevation. While returning home on a 100 mile trip in snow slush and curvy uphill climb at 45-50 mph the car started to squeal loudly. Sound was like feedback from mic to close to a speaker. At first I thought is was the radio going nuts and turned it off. Squeal continued. As I slowed down it decreased as I slowed. Didn't stop squealing until I had braked to a complete stop. In neutral I raced the engine slightly.. no squeal. Back in drive I held brake and accelerated slightly... no sound. Back into drive and pulled away and had no squeal. After a few miles and down the other side of the grade and fairly flat surface the sound came back slightly for a few seconds then went away as I continued to drive. The sound must be coming from the transmission. There is none of the typical slippage or lurching or sound that indicate other transmission problems. Could this be a binding issue caused by uphill torque and uneven wheel slippage? I have searched this forum a couple of places with no luck. I'm looking for tech input with any experience with this issue and/or any suggestions. Need a little ammo for when I take if back to the dealer.

Update: Just checked the AT fluid (cold) and it is NOT a nice red color, rather medium to dark brown. The service records are dealer stamped with regular service/maintenance; but with Volvo maint. scheduled at 105k I would assume no service at all on AT. In the sticky thread on AT fluid, there is a mention of a low speed squeal addressed with the ATF recommended for this transmission. If I can't resolve this issue with the dealer I will be doing a drain and fill flush with Mobil ATF 3309.

 

"Rain Squeal" Known issue.

volvo rain squeal - Google Search

 

Rain Squeal it is.
The lower part of the resonator is being super cooled (by heavy rains/snow/slush) which is making the top half expand upwards and touch the driveshaft. If you put the car in the air, you're able to see the scouring mark on the drive shaft of where the resonator touched it. IMHO the Volvo fix is a big waste of money. They uses a new bracket to move the resonator further away from the drive shaft. It cost's way too much money and gives you less Ground clearance.

Easy fix that we do (me included) is to take your car into an exhaust shop and have them cut out the resonator and replace it with a straight pipe. Should only run you about $60-$80.

 

Thanks Guys!!! Scared the Bajezzus out of me. Thanks for the fix suggestion. I can have a replacement pipe made and do the rest myself. Do you know if removing the resonator will affect California emissions laws?

 

Shouldn't. All the resonator is there for is sound dampening. Has nothing to do with emission controls.