Hey All -

Recently changed out all brakes and rotors and all sway bar parts (links and bushings). Starting to drive really nice (after a year!)

However, there is one thing that i need to get to - possibly it's the front diff (based on some research). What do you think?

If i'm on the highway, i hit 100 kms the noise begins - Grows rapidly from 100- 110 kms. So between 100-115 (60-70 mph) a loud drone (for lack of better description) envelops the cabin. Seems it's from the front (but could be wrong)

There is no wild vibration. No wheel vibration as far as i can tell. I don't think it's a driveline issue (ie. there is no centre bearing shot).

If it IS the diff, how can i check? What else can help me diagnose?

PS) of note, also noticed that first thing - when the car is colder and has been 10-15 minutes in operation - there is very little noise. Only after that. Is there anything that gets "warmed up" that starts to complain like this?

 

Drain the diff fluid. Open the fill plug first, this is easily done with the driver wheel turned full passenger. Need a hex tool, forget the size. Drain into a measuring container to verify how much fluid was in there. Check the plug for metal, I think its magnetic on the front. See how the fluid is, etc.

Also consider the front drive shaft being an issue, they do wear and a joint could be going. Easy to replace.

Well hubs are another possibility, but they generally tend to change noise when chaining steering direction, typically worse pointing one way than the other.

 

Thanks. Will do. Although I did do a fluid swap last year on oil change (only 6k from that time).

Oil was filled to plug overflow. Did note the discussion about how much etc. but went with the general consensus that to the plug level was ok. Overfill a concern more than under?

I expect the drive shaft will move laterally in situ if an issue?

Hubs are ok for now. Checked on rotor replacement for excessive play and there wasn't any...

 

Fluid change means nothing if the diff might be making noise - the fluid can tell you if there is an issue so it needs to be looked at. Of course clean fluid does not mean there is no issues, but dark shaving filled fluid would be a certain sign.

Filling is fine to the fill plug, I did it and others have. It won't cause diff failure. I think LR did it just to keep fleet environmental down.

The front shaft will have nominal play. Its actually better to remove it and check the joints by hand. Because the shaft is pretty much fixed, the joints develop a very specific wear pattern. Same problem with the rear shaft. So when removed you can get a much better feel for things. But they are CV joints so if you check in place there should practically no movement but you probably can move the shaft forward and back length wise.

 

Thanks. I will check and report back.

And if i check the joints, what am i looking for?

 

...any change in the noise with application/removal of throttle?

 

Possibly... Its like it increases then levels off. Then gets louder.

But sometimes its not proportional to how much gas i give it.

What's your thought?

 

...the noise got louder with throttle but it was binary. Like throttle on/throttle off.

 

it’s gets louder. Step off it abates. Step on gets louder.

I took it for a highway run to refresh my memory.

definitely loud at 100kms. By 120kms it sort of plateaus out. Still loud. But doesn’t get louder.

 

...sounds like the front diff to me, but this is a pretty unscientific conclusion.