Ideas?

[Cam]

So, I have a noise coming from the back of the AU (II V8 non IRS).. Issue only occurs over bumps, it has got progressively worse, now sometimes when taking off it will make a similar noise, but seems less of a "metal on metal" noise and seems to come from further back in the car?

Its really starting to annoy the hell out of me, it really sounds like a metal on metal "clunk". In my wisdom I took it to an exhaust shop and hey presto, they replaced my cat! Problem still was there... The exhaust guy did point out that my extractors were close to hitting a few bits and pieces and mentioned perhaps is the engine moving causing the noise, but I am certain its coming from further back under the car. I have also looked at Peuty's car and his extractors have the same amount of clearance, no issue on his car.

After some opinions to what the noise could be? Do I have 2 different noises? a metal on metal clunking and something else?

Argghhh someone help! Slowly going crazy...

[AUbigfoot]

This is most likely going to sound really stupid and not mechanically minded (but no harm in trying to help right?) but I had a similar problem in my first AU in that I had a constant noise coming from the rear somewhere. Looked all over the place under the car, no-one could suss it out.

Turns out that some metal had slipped and gone under the boot carpet and in a hole of the boot. Took a fair bit of fishing, but once removed it cured it.

Just my 2 cents right there..

[Peuty]

Originally Posted by Cam

I have also looked at Peuty's car and his extractors have the same amount of clearance, no issue on his car.

After some opinions to what the noise could be? Do I have 2 different noises? a metal on metal clunking and something else?

Agreed.

Rear bushes maybe?

[Cam]

Not a bad suggestion bigfoot, i actually have a lot of heat shielding under my car which i did suspect could be at fault, but does seem to be. May check that out again

Dan, I am have pondered the possibility of it being the rear bushes, although none of my rear suspension is over 2 years old. I am just not in the situation where I can take the car to someone and hand over a wad of cash to possibly not fix the issue! Maybe I will have to bite the bullet? Arrgghh!

With my back theres only so much I can do by myself, so keen for more ideas before i take it somewhere and hand over cash :

[bodes-sh]

if you can get some help, get someone to lay down and look under the car as you drive off to see if they can pick anything. it could be any number of things...

looking at your sig, i would be looking at the exhaust possible hitting the diff, or vice versa, or the body of the car. a 3.5" exhaust isn't small by any stretch of the imagination, so if there's not enough clearance say over the diff or around the spare wheel well, it could be hitting that when going over bumps.

i take it you can't replicate the noise just bouncing the car up and down yourself while it's parked?

that's just my thoughts on it...good luck and i hope you get it sorted

[private9]

Don't the IRS AU's flog out the rear shock mounts or something.

[tones xr8 427]

i had exactly the same problem, its the rubber bush on top of the diff housing. they split and fall off. i machined up a nylon one to replace it.

[Peuty]

Originally Posted by private9

Don't the IRS AU's flog out the rear shock mounts or something.

Originally Posted by Cam

AU (II V8 non IRS)..

They do, but not the problem.

[BIGJB]

It may not be the shock mount but a shock itself may dodgy and rattling??

[RG]

What is your exhaust, mild or stainless?

[Racecraft]

a worn engine mount that might be letting the engine flex....

[scrivens]

Might sound silly, but have you checked the spare tyre in its well? Mine started making a thump in the rear end which drive me crazy until I discovered that the locking bolt on the spare had been undone completely and the tyre was banging around in the well. Sounds quite similar to shock absorber clunk.

[Cam]

if you can get some help, get someone to lay down and look under the car as you drive off to see if they can pick anything. it could be any number of things...

looking at your sig, i would be looking at the exhaust possible hitting the diff, or vice versa, or the body of the car. a 3.5" exhaust isn't small by any stretch of the imagination, so if there's not enough clearance say over the diff or around the spare wheel well, it could be hitting that when going over bumps.

i take it you can't replicate the noise just bouncing the car up and down yourself while it's parked?

that's just my thoughts on it...good luck and i hope you get it sorted

I tried to get someone to look under the car, but its too low and didn't help much. I have also "shaken" the zorst quite furiously but to no avail, doesn't seem to be close to hitting anything at the back of the car, but certainly worth another look, so cheers!

i had exactly the same problem, its the rubber bush on top of the diff housing. they split and fall off. i machined up a nylon one to replace it.

I will check this out for sure, very possible! thanks mate

It may not be the shock mount but a shock itself may dodgy and rattling??

It is possible I spose, but with shocks that are under 1000km old, I bloody hope not! haha! May have to check it out why the car is on stands..

What is your exhaust, mild or stainless?

Stainless

a worn engine mount that might be letting the engine flex....

This was my number 1 thought, I will dig up some pics of the areas where the extractors had signs of damage..

Might sound silly, but have you checked the spare tyre in its well? Mine started making a thump in the rear end which drive me crazy until I discovered that the locking bolt on the spare had been undone completely and the tyre was banging around in the well. Sounds quite similar to shock absorber clunk.

hahah not silly at all, in fact its highly probable that that's what the second clunk is!

Thanks to everyone for your help, just have to get these last few things sorted and I'll finally be using the AU as a daily again..

[GK]

At least the lads here have provided a long but easy enough list of things to check at no or low cost.

This forum rocks!

I hope you get it sorted out soon.

GK