We just (a few days ago) purchased a 2007 XC90 3.2 with ~115K miles, and so far we really like it.

I have noticed, however, a strange noise and vibration that seems to be coming from the front passenger side. My best description is that it is a hollow and almost rubbery sounding noise that is noticeable, but not at all violent. What I find particularly odd about it is that it seems to be limited -- or at least far more prominent -- in a relatively narrow mph range (~36-41 mph, according to the speedo). It is definitely louder/more prominent while on the gas, but I think I feel it while coasting in that speed range as well. Below that range I do not notice anything. Above ~41 mph there is a slight vibration, but that feels more like a tire/wheel balance issue. It seems to shift smoothly to/from all gears. There is no noticeable vibration in the steering wheel or brake pedal at any speed.

I've had three service techs drive it to get their initial impressions, and 2/3 were puzzled because of the narrow speed range. All were from independent shops that specialize in Euro cars or Volvo/Saab in particular. None of them thought it was anything dangerous, at least at this point. The Volvo/Saab guy, who comes highly recommended, suggested that we drive it until it gets significantly worse before looking to have it fixed. That makes me uncomfortable, as I'd far rather prevent bigger and more costly problems I think we'd get by waiting. One of the other techs suggested that it could be a front drive axle, or possibly a loose bearing from the front to the rear transmission(?). He looked at the boots, and they seem to be OK.

I'm new in this area and have no relationship with any service shops here, so I'm looking to this forum for help before taking it anywhere for work. I have searched for similar posts, but I've not had a chance to search through all the threads. Apologies if this is a common issue that has been covered previously. BTW, I found the Sweedspeed thread (High Mileage XC90 Buying Guide for the Regular Joe or Jane) by SwedishDragon to be very helpful in shopping for a used XC90. The thread (2006-2007 TF-80SC Automatic Transmission Valve Body Issue & Serial Number Info by R-Pow3R3d) by R-Pow3R3d, suggested that certain generations of transmissions have known problems. This truck's transmission is "T07A," which, according to R-Pow3R3d's post, should be more reliable than previous iterations.

Any thoughts would be greatly appreciated!

 

things that rotate include tires, axle shafts and tranny parts. motor mounts (torque rods) can also contribute to vibriations as can wheel bearings.

For starters, have you tried a front/rear tire rotation to see if that changes anything?

Does it change sound if you are cornering vs straight?

Axle shafts for your XC90 are in the $400 range as I recall so you may just want to wait to see if it changes over time. Wheel bearings will also get louder as they wear and there's no preventative maintenance on either of these. You could try a drain/fill on the transmission and transfer case to see if fresh tranny fluid and gear oil helps, but if the transmission has a bearing on the way out, not much you can do short of wait for it to get louder... so about the only things that are practical at this point is to rotate tires, consider freshing the fluids and inspect the motor mounts/torque rods by looking for engine movement when going into gear from park - ie one person "power brakes" the car when the other watches the engine for any odd movement - from the side of the car not in front :-)

 

The upper torque rod and passenger motor mount are common failures but don't exactly match your symptoms. I'd give them a look though.

 

Check the upper torque mount. It should not have much movement in it. If it moves side to side in the aluminum bracket it can make some strange noises and vibration at certain speeds and loads.

 

Thank you for the feedback and advice so far. I have not had a chance to try any of the recommendations, as I have been out of town, but I will post an update when/if I get to the bottom of this.

BTW, would a torque converter be a possible root cause of this noise/rumble? I've searched the web and I have found a couple of reports of similar symptoms and the owners attributed them to the torque converter.

Thanks Again!