Rear end noise diagnostic help

turbotim2 · Post by **turbotim2** » 11 Aug 2012, 20:55

2005 S60 2.5T AWD 113,000 miles.

The car recently started generating a humming noise. The noise starts in at about 35 mph and increases in pitch from there and is tied to the car's speed and not engine speed. There is no noticeable vibration associated with it or any other changes in the way the car drives or rides. I have read through quite a few threads and they have lead me to rear wheel bearing or dirveshaft? What do you think? Thanks for any help!

turbotim2 · Post by **turbotim2** » 13 Aug 2012, 07:34

Anyone have any suggestions? Is there a way to check the driveshaft? The wheel bearings should be fairly easy to diagnose, at least my experience with these is jack the car and pull and push the wheel at 12 and 6 o'clock and see if it moves.

Post by **igel513** » 13 Aug 2012, 14:39

Jacking up a car and pulling and pushing wheel to check if there's play on bearing might not be an accurate way to determine if bearings are bad. If grease in the housing have dried up, bearings will start to wear out and cause humming sound. Once the bearings are so worn out, then wheel will have a play noticeable when you pull/push on it. Isolate w/c wheel is humming then remove wheel hub and manually turn bearing. A bad bearing would turn roughly due to wear.

turbotim2 · Post by **turbotim2** » 15 Aug 2012, 18:14

OK, I took a closer look at the rear end as I had to change the rear brakes anyway. I checked the parking brake components for condition and operation, checked the wheel bearings/hubs, CV shafts and suspension components on both sides and found nothing that would lead me to believe something was wrong.

I took a look at the front end too. The bearings are good but I am a bit suspect of the left front CV shaft. If I grab it close to the transaxle I am able to move it up and down a little, there is some play there and there maybe some play in the joints themselves but it was difficult to tell for sure. My experience with CV shafts is that they start making clicking noises when turning and this car isn't making those noises at all. Just a groan from 35mph+ that increases in pitch with car speed. Any suggestions are most welcome!

adki110 · Post by **adki110** » 15 Aug 2012, 19:20

My 2006 S60 2.5T front wheel drive started to develop a humming noise around 125,000 miles. I pulled all the wheels and checked the suspension,bearings, and axels, found nothing. (used to make my living as a brake and front mechanic) I replaced the wheels and chalked it up to tire noise. The noise continued to get louder over the next 20,000 miles. I replaced the tires and, oops, the noise was still there. Pulled the wheels again and still didnt find anything really wrong, but the right front half shaft had a little (very little) more play than I liked. Got the shaft, pulled the right front apart, and with the axel shaft out could now could feel roughness in the bearing assembly. Replaced the hub/bearing assembly, noise gone. Good luck

turbotim2 · Post by **turbotim2** » 22 Aug 2012, 06:56

OK, Problem solved! After a closer inspection, it turned out to be the right rear wheel bearing. I will say to anyone with a similar issue, the feel of the bearing that was bad is VERY subtle. Look for staining on the outside of the hub from grease. It was an easy job to replace, took only about an hour and with no special tools. The hardest part was getting at the lower rear bolt on the hub. I just used a 15mm box end wrench and a cheater and came right off though there is little room to move in there.