Hi--I love my 2006 LR3 (going on 80k!). I had the dealer replace both front lower control arm assemblies 3 weeks ago. All good (even covered by warranty). But recently, I started hearing a very soft, intermittent grinding sound from the front end. In the last 2 days, it's grown more noticeable, and is now actually loud. Seems to be coming from the wheels.

At off-road height, the sound gets much softer, then returns to loud at normal height. It's a low-pitched grinding sound when driving slow, and increases in pitch as I drive faster.

No doubt there is a problem here, and I'm going back to the dealer tomorrow. But my question is: Could this grinding sound be connected to the control arm assemblies that were just replaced?

As a professional composer, I'm pretty good at identifying the sounds I hear from my LR3, but still learning a lot about the mechanics of this amazing machine

Thanks for any help!

 

It would be wheel bearings, or differential noise. The wheel bearings require a hub change out as the bearings are pressed in. They might also have not tightened and locked your hub nut on. If it is the differential, then they will try to sell you the entire unit at a very high price. Don't fall for it.

This is not directly related to your problem at hand. It would also be a good idea to change your diff fluids (normally LR suggests first service at 75k) I suggest ever 20k. You should also change your transfer case oil and transmission fluid (consider a metal pan conversion).

This work can be performed at a qualified independent shop.

 

Thanks for the advice! So if the noise is the differential, what can I do, short of replacement? Will the fluid change fix it?

 

If the fluid change reveals metal, or contamination it is most likely the bearings are shot. The dealer would prevail upon you to purchase a diff. The parts are available for rebuilding them, which is substantially cheaper.

It is not likely if that turns out to be the noise, that a fluid change is going to cure the noise.

If they're going to have a look at it, lets wait and see the outcome.

 

I hope you are still in warranty cause my money is on a blown diff which is pretty common for FR3's. Get it back to the shop today and pray for coverage.

 

Lucky8 will have it covered shortly Mike

 

By blow differential, what do you exactly mean? c-clips, pins, carriers, etc? I'm coming from Jeep land and am still learning about the LR's so any insight is appreciated.

And another thing; are any of the diff problems wrenchable for your garage mechanic or are we mostly talking certified LR techs/dealers?

thank you in advance,


post script: on topic - any grinding noise anywhere is not good. sound is created by vibrations; vibrations are usually due to friction. Friction is your enemy and a sign of something bad to come. if the pitch increases as speed increases, you can be pretty sure a driveline component is compromised; bearings and hubs most likely, perhaps even a seal somewhere. The good news would be that the transmission internals are most likely okay, since the pitch increases with speed; only the output shaft(s) and other components (wheel hubs, differentials) increase in RPMs as speed increases.

Also, for what it's worth, I don't think the new control arms are at fault. Since the ride height has an impact on the volume of the sound, perhaps the changing of the rige height puts the suspension angles in a compromising position, which increases the load on driveline components somewhere.

I"m just spitballing here so take it with a grain of salt.

 

Yes, particularly if your garage mechanic has some experience with diffs, they can be rebuilt just like any other differential. This means, bearings, seals, crown wheel & pinion, and so on.