Mysterious driving sound

rob6523 · Post by **rob6523** » 05 Jan 2017, 04:50

I have a V70 2.5T automatic MY2007.

Driving at a speed from 10 - 80 miles a knocking sound appears that sounds like a drive shaft problem, the left side drive shaft has been replaced, as wel as the left front wheel bearing are new, and the dealer has suggested to renew the automatic transmissionoil but the sound remains.

Anyone knows where to look or someone who has had the same "problem" ???

Post by **chrism** » 05 Jan 2017, 17:45

Although it may be time to replace the trans fluid, I struggle to correlate dirty fluid with a "knocking" noise.

Are there any conditions under which the noise increases or decreases - like when you step on throttle or let off the throttle? Can you "feel" the knocking in the steering wheel or your feet? Or do you just "hear" it? What happens if you accelerate hard from a stand-still with the steering wheel cranked far to the left or right?

difflock54 · Post by **difflock54** » 05 Jan 2017, 22:32

May be worn control arm bushes, ball joint or strut mount?

rob6523 · Post by **rob6523** » 07 Jan 2017, 08:08

Thank you for your suggestion chrism!

A Volvo specialist said that it is a bad wheel bearing on the right side so I'll replace that after the part comes in.
Strange how the hearing of a sound can be off (hearing the sound on the drivers side where it actually is caused on the right side!)

Post by **abscate** » 08 Jan 2017, 04:23

If it's a wheel bearing noise it will change when you steer left and right. Bearings usually growl or whir rather than knock.

You can also jack up all four wheels and run car to confirm