2007 Auris 1.6vvti knocking noise

[baku911]

Good morning everyone,

I've recently purchased a 2007 Auris, 1.6vvti. 73k miles on the clock. Got it for a bargain of a price, considering today's market prices. It has couple of issues (aware of them at the time of purchase), but since I love working on cars and getting my hands dirty I bought it anyway. 

I've got a metal knocking noise coming from somewhere under the car. Only while accelerating and sometimes on some bumps. Which can also be heard in the video below. Seems like it's coming middle or front of the car. I can't pin point the exact location. But more likely the front. I've examined it underneath and there's nothing loose that could make this sound. Here's a link to a video where you can hear it. For reference, I've placed the phone to record it in the 'storage' hole under the handbrake.

Has anyone ever experienced this noise coming from their car? Any thoughts?

 

Here's my thoughts and potential causes:

1) throw out bearing

2) cv axle (unlikely, tested on full lock around car park, didn't make noise)

3) loose gearbox input/output shaft, therefore one of the gearbox bearings inside of the gearbox. However, the gears go in smoothly, without any grinding or scraping. smooth and no problems selecting/changing gears. Also no whining noise, like it usually is with a bad bearing. To me this possibility is the most likely one, but I find it hard to believe that it's the gearbox shaft. Broken after only 73k? Hmm... On the other hand I've found a video with a somewhat similar sound, but can't aay for sure as it isn't that clear and the guy says it's a grinding/scraping noise

 

So I've been racking my brain and scratching my head for the past two weeks. Can't figure out what it is. I thought I'd seek advice here first, before I go and start taking the gearbox off (PITA on the auris from what I've seen).

 

Any thoughts and advice is greatly appreciated. Thank you

[PCM]

Loose heat shield? Loose exhaust? Spare wheel loose? 

[baku911]

4 minutes ago, PCM said:

Loose heat shield? Loose exhaust? Spare wheel loose? 

All checked. None of those, unfortunately 

[TonyHSD]

Wheel nuts, and thorough suspension check particularly shock absorbers, springs etc. , also all brakes components. But to me sounds like lose wheels, exactly same sound when you place a wheel onto the hub. Can check engine and transmission mounts if you haven’t done so yet. 
Good luck 

[baku911]

Definitely not wheels. I've took all four off and then torqued to spec, because they were rammed on by an air gun. 

Brakes are getting a full replacement, including calipers recondition. One of the brakes is making a separate noise. Nothing to do with the knocking.

Will give suspension another once over, but all seemed fine. Won't hurt to check again.

Engine/gearbox mounts could be a good shout. I'll check those next and post an update.

Thank you for your suggestions