2007 xc90 AWD with 73,000 miles .
When i drive above 30mph I hear a knocking noise coming from the front center or right side) This noise only happens when I accelerate once i let go of the accelerator it goes away. When i shift into neutral it also goes away. When i go uphill it gets louder Turning left or right does not produce any noise. The knocking noise goes faster as the car goes faster. Does not match the revs of the engine.

 

2005 XC90 AWD T6 ~94,000mi

Mine just started something very similar. It sounds like the knocking is coming from the front left wheel. When it started I pulled over and looked for something stuck in the wheel as it sounded like something slapping against the "spokes" of the wheel. The knocking comes and goes seemingly at random, but when it comes, it's quite loud.

Searching for a solution on the interwebs only returns solutions for suspension problems. I have a hard time believing this to be a suspension problem as the knocking is in time with the speed of the wheel, not the RPM of the engine and is very rhythmic.

Mine does not seem to change when accelerating or coasting. It has manifested at low speeds around 10-15mph and at highway speeds of 60+.

I realize I have not offered any solutions here, but I feel better knowing that someone else is having a similar issue. Have you found any solutions?

 

did you find the problem? I have the same one. I had the dealer check and they said it was the u joint and I need to replace the driveshaft. I did that and still have the same problem-needless to say not good.My car is a 2008 XC90 with 75k miles.

 

I did. It was one of the cv joints on the drive shaft. Continuing to drive with the knock eventually made it worse. The knock turned into a vibration that shook the car so badly, I didn't dare drive it faster than 20mph. I limped it to a buddy's auto shop and put it up on a rack. We spent about 20 minutes trying to determine which of the two cv joints were bad. The front cv joint runs about $300 for parts. The center cv joint is non-serviceable. I didn't want to chance wasting $300, so I replaced the entire shaft. I ordered a rebuilt shaft from coloradodriveshaft.com. They shipped out the replacement the next day. I wanna say it was around $700. Once I swapped the shafts, I packed the old one back in the box and shipped it back for a $100 core refund. Everywhere else wanted over $1000.

Took about 30 minutes to swap out. Really simple to do. You remove the exhaust pipe from the header to get to the shaft. There are some support brackets to remove and then it's just a few alan head bolts on both ends. The shaft drops straight out. No seals or bushings to mess with either. The new shaft is smooth and quiet, and I'm still driving it.

The issue is a result of a poor design by Ford on these Volvo XC90s. The drive shaft and the exhaust run down the same center channel. To do this, the transmission is offset to the right allowing the exhaust header room on the left. This requires a cv joint on the front and middle of the shaft. The exhaust runs along the entire length of the shaft underneath it constantly exposing the shaft, both cv joints, and the u-joint to extreme heat. This causes early wear and fatigue. I suspect I may be replacing the shaft again before I hit 200k.