Thumping / rumbling noise from rear - 2001 Outback LLBean H6-3.0

[kkmft]

Thumping / rumbling noise from rear - 2001 Outback LLBean H6-3.0

 

There is a very brief rapid thumping/rumbling noise

- comes from the right rear

- occurs when driving over sharp rise in road at speeds over 45-50mph

- when making long right turns like on a freeway onramp

- occurs only when the vehicle is extended highest on the suspension

- when rear struts are fully extended

- and only when the car is empty of any extra weight load/cargo/passengers

 

thumps/rumbles noise at various speeds, and the sound varies with speed

 

The noise has become easier to reproduce, sounds like its getting louder

 

Mech. visual insp. found nothing in the suspension that loose or worn out.

Mech. drove the car alone & reproduced the sound, but didn't find the source of the noise.

 

Any ideas? Propeller shaft? Rear axle? Rear strut mount? Rear hub bearing?

[1 Lucky Texan]

how many miles on the car? Our 03 had a blown rear strut at 65K. the others were weak (I changes all 4)

 

did you or the mechanic lift the boots and feel for oil on top of the cylinder?

 

About the only other things I can think of - I read that springs can be broken in such away that it's very difficult to see, but they will fall apart when removed from the strut.

 

also, you might look at the bolts on the floor under the rear seat-back - just to see if a head hasn't broken off or something weird like that.

 

Also, under some of the conditions you describe, the rear anti-sway bar is gonna be tweaked hard so - it might have a bad mount or something odd with a link?

 

those all the w.a.gs. I have lol!

[kkmft]

It has 165,025 miles on it. I know, it's a mystery where this noise is coming from. I keep hearing it only when the strut is R-reary fully extended, and it does sound directlly correlated with RPMs. I'm not sure the mechanic lifted the boots and felt for oil on top of the cylinder, but I'm taking it in again & will have him do that. Thanks

[1 Lucky Texan]

It has 165,025 miles on it. I know, it's a mystery where this noise is coming from. I keep hearing it only when the strut is R-reary fully extended, and it does sound directlly correlated with RPMs. I'm not sure the mechanic lifted the boots and felt for oil on top of the cylinder, but I'm taking it in again & will have him do that. Thanks

 

 

well, at that mileage, many bushings could be suspect, and original struts HAVE to be worn out....but it would suck to swap out struts and still have the noise so, still need to do some good diagnosis on the suspension. Might be worth inspecting the brake calipers and check the wheel bearings though - they I wouldn't expect a loud knock from them. Even check the wheel studs.

Edited September 1, 2012 by 1 Lucky Texan

[nipper]

Start with something simple. Rotate the tires, one side at a time, and see if the sound moves.

[kkmft]

thanks nipper for the suggestion, I've first noticed the sound last spring, rotated the tires in July - the sound didn't travel with the rotated tires.

 

and yeah Texan, I agree the struts are probably toast, and it would definitely suck to have the struts replaced and then still hear the noise

 

thanks!

[CNY_Dave]

I had a rear wheel bearing start making noise at about that mileage.

 

Up to 180K and it almost needs replacement.

 

If someone who knows what a bad wheel bearing sounds like can hear it, it is quite distinctive.