Hi all, I have a 2002 Discovery 2 V8 automatic and I've been chasing a front end noise with an unusual pattern. Posting here to get some experienced eyes on it before I start pulling things apart.

The noise: Starts as a chain-like rattle at low speed and chirps at a faster rate as road speed increases. The frequency tracks road speed directly, not engine speed.

When it appears: Coasting, light cruising and braking.

When it disappears: Under heavier acceleration load, and completely when stationary regardless of engine RPM.

Other observations:

• Front of vehicle only
• Silent when cold, appears only once warmed up
• No change when steering left or right
• Cannot be reproduced in neutral with the vehicle stationary

The warm-only, load-sensitive behaviour is what's puzzling me most. It goes away under power, which suggests something is being loaded up and silenced under acceleration, then rattles freely when that load is removed.

Videos attached showing the noise at various speeds. Apologies for the coffee cup.

Any thoughts on what could be causing this pattern and where to start looking would be much appreciated.

https://www.icloud.com/photos/#/iclo...27AdWXc-Jmg/0/ (Highway speed)
https://www.icloud.com/photos/#/iclo...0lnQAJxIsHA/0/ (Low speed, starts at 8s)

Thanks

 

Have you checked out your front driveshaft?

 

Yes, I just replaced it with a luck8 one and greased it. Could it be that I didn't grease them properly?

Teo

 

With a grease gun, right? You added grease until you saw grease coming out of the seals, right? If so, then you gave them enough; but did you grease all of them? Five spots need grease: the single cross at the axle; the slip joint; the two crosses in the double cardan at the xfer case; and the centering ball between those two.

 

Yessir, but perhaps you're right and I missed one of the five nipples. I'll grease it tomorrow and try it out. Will post here.

 

That's a difficult one. Low speed kinda sounds to me like when I had a rusted/bent caliper backing plate very slightly rubbing on the inner brake rotor. It would only show up with heat, and continued no matter steering direction. However that is a decent speed in the highway clip for that kind of noise to persist, so that may be a red herring.

 

Remove the driveshaft, lock the transfer case differential, drive it.

 

my son had a strange noise on his 2000 disco...did the same thing to diagnose the front driveshaft. sure enough with it off and diff locked
noise disappeared.

 

Got the grease gun from my folks today, will grease up the prop shaft again and see what happens

 

Definitely try it with it removed. Also will need to remove it to get to all the nipples.