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Discussion Starter #1
Apologies for this being a bit long winded, however I really would appreciate any thoughts to rid me of unwanted noises coming from the front axle.

I have a noise coming from the front axle which I can only describe as a low pitched light grinding / binding / dub-dub sort of noise which is consistent with rotation of the road wheels. The noise is barely audible at any speed when driving in a straight line or in a RH bend, however is most clearly audible during a moderate LH bend (with A/C and stereo switched off), typically noticeable when going around a roundabout at approx 20-30 km/h (ie/ anticlockwise). It’s been making the noise for the last month or so now and has very slowly become increasingly audible over the last 1,000 kms. It’s a 2001 vehicle with 161,000kms on the clock.

I’ve done a thorough search of this forum but not come up with anything else that clearly resembles the cause of my symptoms. Judging by the search results it seems that CV joints on p38’s do not fail with regular occurrence, and neither worn wheel bearings nor front differentials produce the same sort of noise when they require attention – typically more of a constant grinding / whirring noise. I had new bearings in the front diff approx 15,000kms ago which cured a whining noise. Even though this new noise is most pronounced on a LH bend, I just can’t decide whether it’s coming from either the LHF or RHF, however I’m more inclined to think LHF which goes against common sense which tells me that the noise would more likely to be coming from the RHF wheel which is under load in a LH bend.

In an attempt to track down the source of this dub-dub noise I’ve done the following:

Lifted front axle up on stands, rotated front wheels by hand in dead ahead position, turned to LH and RH, but can’t really hear or feel anything. Push / pulled the front wheels at top / bottom but no sign of any play or slop in either of the wheel bearings.

Visual inspection of CV joint boots – no splits or signs of leakage.

Visual inspection of brake discs (rotors) and pads – all in good condition with plenty of friction material on pads and no evidence of any cracks or warped discs. Braking the car does not affect the noise in any way.

Removed the front propshaft and driven around but the noise is still there, therefore only eliminated worn U/J’s as the cause.

Passenger sitting with head in passenger footwell, ear to loadspace floor and whilst sitting in rear seats, which has only confirmed the noise is coming from the front of the vehicle.

Driving in a big open car park at varying speeds and degrees of turn both LH and RH circles the dub-dub noise is most pronounced at about 1/3 lock on overrun in a LH bend at approx 20-30 km/h. At full LH lock I can’t hear it at all. No noise in reverse.

There are signs of light rubbing from the tyre on the RHF inner wheel arch plastic liner, but have since eliminated this as the cause of noise.

Swapped the wheels from front to rear - no change in noise.

With a mate standing still, driven circles around him – no unusual noises can be heard from outside the vehicle.

Changed the front differential oil (yesterday) which was only previously changed <10,000 kms ago. Old oil was reasonably clean with moderate build up of very fine metallic particles on the magnetic drain plug, but nothing unusual. No change in noise.

Also noticed that diff oil has been seeping out of the connection between breather tube and where it connects to the top of the front axle – it’s only started leaking very recently, possibly coincides with the dub-dub noise which started a month ago – any ideas what would cause this? blockage in breather pipe? pressurisation in axle, but why?

I’ve also had a few local independent Land Rover workshops listen to it and have been told it could be either a RH wheel bearing, a LH CV joint, or even a bad viscous coupling in the transfer gearbox (which just doesn’t make sense to me)

Thinking it might be a bad CV joint, I’ve already bought a new one but just can’t decide which side to replace, if at all.

Being of Scottish ancestry I’m loathe to spend cash unnecessarily and therefore want to avoid replacing expensive parts on a trial and error basis, so would appreciate any further pointers how I can ‘hit the nail on the head’ to rid me of this noise once and for all.
 

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G'day Big Red, i would say your diff is on its way out again?????/ If you didn't replace the ring and pinion when it was rebuilt i would say that is the metal in your diff oil.If your breather was block most likely to cause a pinion seal leak ,oil out of breather is most likely caused by over filling of diff, excessive diff temps from failing bearings or pre-loads,caused buy one side of the diff carrier bearing failing which is what you can hear :think: A woooo woooooo sound it is :?:
You would of red the other posts on similar noises death wobble etc,so you may of done the cheaper checks first,like rebalance wheels, re-do wheel alighnment with zero toe in.
Then go with your insticts do the CV test,see other posts,then while its being done do the wheel bearing as well. If it doesn't fix it ,then go the dearest, new diff!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

Good luck
Regards Graeme.
 

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Hey Big Red, this is Big-T, I am having what sounds like the same problem as you are. So far I've torn the front end down completely and can't find a bloody thing, no bad bearings or cv joints and just like you I changed the diff fluid and had a couple off tiny, tiny flakes of metal and clean fluid and am tearing my hair out trying to fix this VERY annoying problem. So far just in the last 6 weeks since it started on a drive one night through a really heavy rain storm it has cost me a cross Canada trip to see my relatives in Newfoundland, whom I found out after they were planning on throwing me a big bash for my 50th birthday, then I was supposed to be in Vancouver British Columbia to visit my sisters and brothers ( I'm the youngest of 8 ) and they were going to throw me a bash on july 11, my b-day, and have had to cancel both due to lack of transportation. I swear I'm losing it :lol: not to rattle my own chain but , dam it, I am an excelent mechanic, I am actually a Power Engineer and can usually diagnose problems with cars instantly and get stuck fixing all the wifes friends cars and friends tell their family and so on. If you find the problem please share it with us , my post says" help meeee,01 4.6 diff howl ",Today I'm going to take the mass damper off and try driving it and then if thats not it I am thinking about replacing the control arm bushings. Anyway, good luck and keep in touch, Big-T. My symptoms are a very annoying howl like HUMMMMM then it stops then HUMMMM then it stops but only between 52 and 75 mph. Have a look at my post and it will show you what I've been putting up with, again, Good luck. :cry: :cry:
 

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If it is not the bearings either side, it is probably one of the bearings, either side. If not, replace the cv joints, and mark the difference. :think:
 

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Discussion Starter #5
Thanks for ther replies guys.

Graeme - it's a low pitched 'dub-dub' sort of noise, consistent with wheel rotation, most audible on LH bends, but only from inside the cabin. Don't hear it for the first 500m when driven from cold, only once lubricants have warmed up a bit.

Big-T - it may sound silly, but have you checked for a loose wheel arch liner rubbing on a wheel? Bahrain isn't very big so I'm never more than 15 kms away from my trusted workshop - if it suddently gets much worse it's not a big deal for me to either drive it very slowly or spend $25 having it transported on a flatbed truck.

Stephen J - which bearings are you referring to? wheel bearings or bearing(s) within the diff?
 

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you mentioned that it doesn't do it until the fluid gets warm, well guess what?, mine does the same thing, ha, good luck to both of us. I know it's not the inner liner as I have had the whole front end apart and can't find it. :crybaby2: I'll keep you up to date on my progress or get the wife to contact you should I end up in the nut house over this. :lol:
 

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Sounds more like a bad tire or wheel bearing, but you really need to use a scientific method to pin point it. I personally use Steel man electric ears when I come across a noise complaint. It is a battery powered headset with rotory switch , 6 color coded mini clip on microphones and 20ft leads.
It allows you switch to each mic seperately . A reed tach(an old school tool) could also be used to determine the frequency of the noise you can then link it with a component speed(Propshaft, axle,or wheel).
Hope you can find this useful
 

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Discussion Starter #8
Big-T - as well as myself at least 4 other mechanically minded folk have had a listen, and no one is willing bet a months wages to guess exactly what's the cause of my dub-dub noise. It's best not to get our wifes talking to each other - mine already thinks I'm completely crackers spending so much time getting crawling around under my RR in 40+ celcius heat!

Goatwerks - It's definitely not the tyres - I've swapped front to rear, and also tried different pressures. Great idea, but I really don't expect to find a workshop in Bahrain with any such scientific listening devices.

I think I can now just about feel a slight buzzy vibration coming through the drivers footrest / floor. I've decided that since I've already got a brand new CV joint I might as well have it installed this weekend, and have opted to go for the LHS (drivers side). While the hub is off I'll also have the wheel bearing investigated.
 

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Big red, Last night I found that the front u-joint on my rear diff has a broken off grease nipple and it doesn't look like it broke recently so after greasing the rest of the joints and driveshafts and getting mud and water coming out of most of them I've decided to replace all 4 u-joints today and when I think about it the rear drive shaft is connected to the tranfer case, the tranfer case is connected to the transmission, and the trans is connected to the engine witch is connected to the frame rails up front so my vibration could definetly be coming from the front of the back drive shaft and tricking me into thinking it's a front end problem. It wouldn't be the first tricky diagnoses I've come across. Best of luck, let you know how it turns out later, Big-T.
 

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Well Big Red this is Big T and I finally fixed my problem. you have to go to my other thread at : vibration in 01 4.6 hse drive train :to watch the videos and pics of what it was. You won't beleive it, it was so stupid and yes, another cheap fix, I can't believe it so please check it out and I hope your problem is so simple and easy, good luck, I'm going for a long drive and take my wife to the top of a mountian and run around naked, :lol: :dance: :clap: :clap:
 

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Discussion Starter #12
Big-T - congrats at resolving your problem, it's probably best to keep your clothes on though.....

I'm still systematically eliminating possible causes of my dub-dub noise, starting with the cheap stuff first.

I replaced the LH CV joint at the weekend and inspected the wheel bearings - both were OK and my noise is still there. I was absolutely convinced the noise is coming from the LH front, but it's obviously not.

The dub-dub noise seems to have become less noticeable around bends, however it's now becoming more noticeable under straight line acceleration from 70-100 km/h, and then fades away when on the overrun.

I think I'm going to remove the rear driveshaft next to see whether that has any effect - another cheap test.
 

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Discussion Starter #13
To put closure to this thread I'm pleased to say that it's now fixed, which is a big relief after having driven around for quite a number of weeks with my ear cocked towards the dashboard listening for the source of the noise - It was the front RH wheel bearing that was the culprit.

Before pulling the hub I had the car raised completely off the ground resting on 4 axle stands (each 6 tonne rating) and then ran it up to 100km/h, which confuses the traction control and is quite scary when in close proximity to the spinning wheels, but it revealed that the dub-dub grinding noise was definitely coming from the front RH wheel area.

So once again my RR is a real pleasure to drive.
 
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