I have an 08 LR3 with 136K miles that is making a growling/grinding sound the I believe is coming from the front diff. There is almost no change in the sound with change in engine rpm or vehicle speed. I do not really hear anything with the windows down only with the windows up.

I changed the front diff oil recently and the plug had a lot of shavings/black sludge stuck to it and the fluid was dark and metallic. Since changing the fluid it has gotten noisier. My question is how long can I drive on the noisy diff?

 

The answer is until you can't. There is no way to know how long it will last. Could be a day or 10 years. Check and change the fluid again. The amount of metal in the fresh oil should give you a hint at how fast it's eating itself.

Check with Abran here on the forum he may have a good used unit for sale.

 

For what its worth, if you have not changed the fluids in the T-case or rear diff, I would also do those too.

 

I did change all three fluids at the same time. T Case and rear diff fluid looked much better than front diff.