Help chasing pulsing groaning sound Topic is solved

LAV70R · Post by **LAV70R** » 30 Jul 2025, 08:38

Howdy,

I have a 2007 V70R with 180K miles, and have an issue where the car makes a pulsing, wub-wub-wub sound when there is any load on the driverside of the car (roads banked downwards to the left, or even the slightest right turn of the steering wheel). I can feel a vibration under the driver's floor, but not in the prop-shaft tunnel.

Chasing this, I have:
Flushed the bevel gear oil
Replaced front and rear driverside wheel hub
replaced front driverside axle (both otiginal and replacement were from volvo)
Replaced the top and lower (passenger side) motor mount
Verified no rubbing of dust shields

Attached is the audio, it's a subtle sound--but any and all help hunting this down would be greatly appreciated.
FWIW I have meticulously maintained this car myself for the last 15 years and only used volvo OEM parts throughout--i.e. no need to suspect shady oem replacements

Many thanks in advance!

LAV70R · Post by **LAV70R** » 30 Jul 2025, 08:40

PS, in the audio clip, it's a background rotational sound--and unfortunately, the droning's volume changes throughout the clip (as it does when driving). This recording was made at around 70mph

Vova585 · Post by **Vova585** » 30 Jul 2025, 08:44

Hard to tell anything based on the audio clip.
Given your symptoms and millage i would be suspecting angle gear sleeve vs angle gear splines being worn.
You can possibly disconnect driveshaft and try to drive it like that. If no symptoms- problem is within angle gear.

LAV70R · Post by **LAV70R** » 30 Jul 2025, 08:57

I should know better than to think my car is immune from common problems (after all my original block cracked after chasing false leads for weeks)— but angle gear sleeve seems to be less of a problem in late model p2s, and at least the inboard splines on the look great.

Do you think angle gear could still be at fault given that any left turn off the wheel makes the sound disappear?

I have not yet replaced the transmission mount and it’s very soft… the shocks have no leaks, therefore the only other suspension related thing I could think of was possibly passenger side front wheel hub (eg if the vibrations were manifesting in the differential/angle gear). Doesn’t make sense as this should make noise on left turns only, but I’ve read of one or two similar cases in the past. No idea of the passenger axle carrier bearing is ok or how to check…

PS the sound in the video is about 3 times per second but at this speed wheels turning at 15 times a second and angle gear 45 times if my math is correct!

Post by **jonesg** » 30 Jul 2025, 09:38

When I get noises that aren't obvious enough to pinpoint i turn the radio up. It always gets worse in the end.

LAV70R · Post by **LAV70R** » 30 Jul 2025, 10:44

jonesg wrote: ↑30 Jul 2025, 09:38 When I get noises that aren't obvious enough to pinpoint i turn the radio up. It always gets worse in the end.

Agreed, but as I’ve aged, I’ve begun to worry about the type of stuff I never did as a youth; ie catastrophic auto failure and so my search isn’t for perfection, but rather what preventative maintenance to prevent catastrophic failure

LAV70R · Post by **LAV70R** » 30 Jul 2025, 10:48

Another update: pulled the abs fuse and the sound persisted, so it isn’t the and firing while turning right…

Post by **jonesg** » 30 Jul 2025, 16:15

you could try raisng all 4 wheels on jackstands and running it up...just don't get under it.
Did you try unplugging the haldex fuse in the rear panel.?

Post by **vtl** » 31 Jul 2025, 07:29

As Vova indicated, it cut could be the worn splines in collar slave + angle gear.

In my case it was a slack in transmission's final drive / differential preload. I got rid of it only by rebuilding the transmission. Over time / miles preload shims get crushed into transmission's case, the free play lets the axle walk away and become non-coaxial so lightly. This puts load on one spot of the bearing race, it finally picks up and grinds through the case, accelerating wear and wub-wub-wub noises.

I saw another AW55, with twice less miles, and it had the first signs of the spinning bearing race. The transmission guy who made dozens of them, said it is a very common problem. They all do it, just give it enough time.

: Screenshot at 2025-07-31 09-24-37.png (1.13 MiB) Viewed 174 times

Post by **vtl** » 31 Jul 2025, 07:31

I actually have another AW55 sitting in the corner, it had the same wub-wub-wub problem when it was in the car. Have no time nor will to split it up and check what's inside.