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Fg turbo ute rear knocking

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So I wedged some bike rubber in between the front leafs and it still knocks.

 

I read elsewhere that the lsd clutch packs can knock on take off as they come together? People recommend changing the oil but I've done that and made no difference.

 

Completely lost on this now 😑

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Was thinking about doing that. I'll have to find one to try out

 

I pulled the spare out and tried laying under it with a creeper while my old man slowly moved forward, he was a little iffy with the clutch work so gave up on the idea. Definite clunk from the wheel zone from the little chance I had while under there.

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Could possibly be stuffed axle bearings if its coming for the wheel area. Check for side to side play of the wheel hub by jacking up and pushing/pulling on the wheel.

 

Ute's are notorious for making noises, and they tend to come and go. I just turn the music up

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I'm usually an advocate for ignoring strange noises but mine sounds and feels like the ass end is going to fall out when I take off after a good 30 mins or so of driving but perfect when cold

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I've checked wheel movement and all good in that area. Like I said I don't get any vibration or noises while driving, it's all on that initial take off and around really slow corners. I must say mine generally won't when cold but once its been for a good run like on a highway the driveline feels really slack and the rear knocks are petty loud.

 

There are tonnes of posts on here about this issue but no one has come back and given their solution haha

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I had exactly what your talking about, and it was the centre bearing. If its manual the driveline slop is standard as it gets warm, and you will always get a clunk if you disengage the clutch too quickly. If the noise/vibe relates to clutch movements, and/or you get in certain gears or more so in some than others then it's most likely driveshaft balancing (This wouldn't affect noise/clunk on take off though). I had a clunk when turning and it was my twin 3"exhaust slapping the chassis rail so worth checking that

 

I have a twin plate ceramic, built 2 piece shaft and true-trac diff with around 500kw, as you get familiar with the car and you learn how to drive it and you can drive around the slop easily from good clutch engagement and steady throttle movements.

 

I don't know where you are but pay G&J Drivelines a visit, and steer clear of pedders and go to experts like centreline suspension or advantage suspension if in Melb

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The car is dead stock except for the superpro stuff and konis and the knock was there before I changed everything. Definitely not the exhaust hitting. Its a very audible clunk from the wheel zone.

 

I know the bearing is starting to flog out, I can hear it wobbling at low speeds and get the driveline clunk/shunt if I don't try and really control it.

 

Been to pedders twice and they've just tried to upsell me. And the driveline joint was stumped.

 

Is it possible that the center bolt in the leafs has come loose? Is that a thing?

 

I'm in Geelong so Melbourne isn't too far away for me. Centreline in thomo is probably the closest out of those. I'm almost convinced its something with the leafs.

 

What centre bearing did you put in?

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So I've thinking about the gaps in the leafs and was wondering if anyone else's are like this? It doesn't look like they're clamping down firm enough? The top two have gaps but the bottom three look tight. Could this be the centre pin come loose maybe? 

 

0g4YnD8.jpg

 

QLKij6A.jpg

 

 

I noticed the non xr utes have a different setup, two steel plates and no u bolt housing:

 

IMG_2687.JPG

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Ideally you want to do what the non xr has.
The bushes flog out so quickly.
The only issue you'll have is if you remove the metal saddle setup and bushes you'll have trouble lining the diff up as the bush is what centers the diff on the leaf.

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I reckon so. I can get some solid leaf saddle bushes from a bloke in QLD but that'll cost a bit. And I'm not convinced it'll fix the problem just yet. I feel like it needs a solid plate under and on top to pull them together more.

 

So I caught up with a mate who has an FG xr6 turbo ute and we compared leafs

 

These are his:

glGPwaZ.jpg

 

blsNeKV.jpg

 

 

These are mine:

k2kE7RO.jpg

 

DomOvJ5.jpg

 

 

They look like two completely different leaf packs?

 

His has a steel plate between the leafs and saddle bush.

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Guessing his is second hand.
Yours are normal and the same as my Ute was.
His have had the "helper" or "overload" leaf removed and the steel plate added to take up the slack between where the leaf was.


Removing the bushes was the best thing I did for tightening the rear end. If anything it will add noise which should help isolate the issue if that wasn't it.

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I didn't replace them.

Removed them and the steel saddle brackets completely.

Then drilled our a peice of round stock to fill the gap where the bush would have been between the leaf bolt and hole in the axle housing plate.

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I bit the bullet and threw in some solid steel saddle bushes and it hasn't made a difference to the sounds. I did notice that between each leaf through the middle there are steel plates, maybe 1mm thick. That's what's causing the illusion that there is gaps in the leafs. Is it normal that they have these thin plates through the middle? My mates leafs are completely sandwiched together.

 

Also noticed when jacking the rear up the wheel has some back and forth movement, a couple mm. But not in and out. Is this just the slack in the diff/gears?

 

Also got a centre bearing as that has collapsed from the top.

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To the OP I had similar symptoms in my FGII xr6t Ute with 90k on it, though mine is an auto. Ended up requiring a new LSD and center diff bearings, which completely eradicated the noises. The car is extremely quiet to drive now. 

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I have a FG MKII NA Ute doing the same sort of sounds. Multiple clunks on acceleration and a single clunk -sometimes- on decel. Doesn't happen when car is cold, and happens a lot if I'm in traffic moving at 20-40kph. have 68k on the clock and have had the sound for a fair while now. Finally took it to a mechanic the other week to which they checked over the whole thing and didn't find an issue other than "it's your leaf springs". He didn't really have an idea as to why they were causing a sound in particular. When listening it definitely does seem like it's coming from the springs on drivers side, but at the same time the clunk on takeoff isn't just a single clunk, it will go sort of CLUNK-clunkclunkclunkclunk sometimes. Also noticed sometimes when pulling up to a light slowly, the closer I get to stopping I get a clunk..clunk...clunk.....clunk. It's really weird and hard to replicate. Also you can hear a thunk in the rear when going over a speed bump or a decent bump in the road, almost like something is bouncing in the tray. Haven't tried much yet apart from getting the diff oil changed, which did nothing. If anything the noise got slightly a bit worse in traffic. Maybe I'm thinking them having the springs fully unloaded on the lift made it worse somehow? I have no idea. I'm pretty useless with cars if I'm honest but I'm learning a hell of a lot in the process of trying to find the cause and solution to this. Going to check everything is tight underneath, despite the mechanics saying everything is tight and nothing is worn. Might try to put something between the springs or something. Bleh.

Edited by JasonHyde

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19 hours ago, JasonHyde said:

Also you can hear a thunk in the rear when going over a speed bump or a decent bump in the road, almost like something is bouncing in the tray. 

Check spare wheel is tight underneath for this noise

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On 31/10/2019 at 7:11 PM, JasonHyde said:

I have a FG MKII NA Ute doing the same sort of sounds. Multiple clunks on acceleration and a single clunk -sometimes- on decel. Doesn't happen when car is cold, and happens a lot if I'm in traffic moving at 20-40kph. have 68k on the clock and have had the sound for a fair while now. Finally took it to a mechanic the other week to which they checked over the whole thing and didn't find an issue other than "it's your leaf springs". He didn't really have an idea as to why they were causing a sound in particular. When listening it definitely does seem like it's coming from the springs on drivers side, but at the same time the clunk on takeoff isn't just a single clunk, it will go sort of CLUNK-clunkclunkclunkclunk sometimes. Also noticed sometimes when pulling up to a light slowly, the closer I get to stopping I get a clunk..clunk...clunk.....clunk. It's really weird and hard to replicate. Also you can hear a thunk in the rear when going over a speed bump or a decent bump in the road, almost like something is bouncing in the tray. Haven't tried much yet apart from getting the diff oil changed, which did nothing. If anything the noise got slightly a bit worse in traffic. Maybe I'm thinking them having the springs fully unloaded on the lift made it worse somehow? I have no idea. I'm pretty useless with cars if I'm honest but I'm learning a hell of a lot in the process of trying to find the cause and solution to this. Going to check everything is tight underneath, despite the mechanics saying everything is tight and nothing is worn. Might try to put something between the springs or something. Bleh.

Does yours have an LSD?

 

Mine is definitely most noticeable from the passenger side wheel area but will sometimes get the double clunk. I got the centre bearing done and that eliminated some things but the rear clunk is still there.

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