Knocking/tapping sound - 2004 Outback N/A

[ross1221]

Hey Guys,

First off, I'm no mechanic but I do have common sense and google so I have explored (what I think to be) the simple solutions already

The problem:
In simple, once I have driven the car for 15-20 minutes and it has warmed up, at low speeds below 2500rpm I can hear a slow ticking from what sounds like the front left wheel hub. It will happen whether I turn or drive straight. I can hear it in first, second and third gear but can not travel slow enough in fourth or fifth to hear it over my exhaust/road noise. It only happens under acceleration, not while revving in neutral or coasting and does not follow the revs, meaning it is a constant ticking/clicking speed no matter the rpm. The noise is also only audible when I have the aircon and my music off. It is the same as this video here: https://www.youtube.com/watch?v=AXh5wurWsnA

Othe info:
So recently I took my manual 04 Outback to the sand dunes and bashed it around a little bit and did the front left outer CV ( i had clicking/clunking while turning left and accelerating - much different sound to what I have now). I Purchased an eBay drive shaft and soon realised that was a mistake and sent it back. I then went to the wreckers and purchased a used drive shaft, installed it and all was good. A month or so ago I started hearing the noise stated above and I replaced the left wheel hub (thinking this was the problem) with yet again another product from the wreckers, but still had the same noise. I then changed the wheel hub from my right wheel to the left wheel and visa verse to see if the noise swapped to the other side (i also swapped over the drive shaft I got from the wreckers just to make sure that wasn't causing the problem) but I had no luck and the noise was still persisting around the front left region of the car. I am now beginning to think it may be transmission/diff or engine related, with maybe the positioning of me in the drivers seat making it seem that it is coming from the far left of the car.

***UPDATE***
**I just took the car for another test and if I get the car rolling, put it in neutral and rev freely to about 1500rpms i can produce the noise until the car comes to a stop.**

I appreciate any help I can get and am open for any suggestions! let me know if more information is needed
Cheers Guys!

[Brendan_P]

I'm not saying this is definitely it but I had a similar issue with one of previous liberty's and it turned out to be the fluid coupling in the gearbox.

Hoping I'm wrong cause that isn't an easy fix.

[ross1221]

I'm not saying this is definitely it but I had a similar issue with one of previous liberty's and it turned out to be the fluid coupling in the gearbox.

Hoping I'm wrong cause that isn't an easy fix.

Thanks for the reply Brendan,

That's related to the viscous coupler in the transmission right? if so i also hope that's not the case, cause that is damn expensive I've heard. I will do some research and see what the symptoms are, and hope for dear life that they aren't what im experiencing haha

[Brendan_P]

Yep that's the one.

[ross1221]

I'm not experiencing any diff binding or anything of the sort so i don't think that's the problem. And on top of that the noise is only coming from one side of my car, rather than from the middle, so fingers crossed that it's not the viscous coupler. If i can't figure it out in the next month or so, ill send it off to the mechanics.

[ross1221]

*UPDATE*

I was able to get an audible video of the sound, i took the video sort of in the glove box with a few bits of interior taken off. I had the car jacked up on all four, in first applying throttle to 1.5k revs. It kind of sounds like its something rattling in the video but it's a distinct ticking that only happens when the accelerator is pressed and seems as though it is coming from either extremely close to the firewall in the engine bay, or more likely behind the far left corner of the glove box. here is the video https://www.youtube.com/watch?v=JRQHILFscdE

It kind of sounds like it is coming from near the ignition relay, im not sure if that could cause a ticking noise? or some other electrical component around that area?

any suggestions from anybody are welcome

cheers

[tom_kauf]

Hmm, I couldn't hear what usually sounds like a Centre Diff clunk in the video. If that's what is meant by viscous coupler in the transmission....
I've had the centre diff replaced, and yeah it's not cheap.
I didn't notice any diff binding either, just a noise when turning at low speed. But you mentioned you also get the noise when going straight, which isn't usually a symptom of a Centre Diff issue.

EDIT: But you mentioned the noise appears when the car is warmed up. That is a symptom of a Centre Diff clunk.