I have a 2002 Discovery.
It is making an awful noise from somewhere in the front end. It happens a only a little bit on accelleration, but is the loudest when I take my foot off the gas and just coast. It is sort of a grinding, mechanical noise.

Any ideas on what it could be? I just had the brakes done, so it's not that.

Thanks in advance!

 

The first thing I would do is stop driving it. Then I would make sure there is fluid in the front axle's differential (easy to do). Then I would replace the u-joints in the front driveshaft if you don't know their history and before it destroys your transmission. (I would replace them even if they aren't making the noise).

 

How many miles on your truck? Have you replaced the front u-joints yet? I agree, do not drive it till you get back to use. If it is the u-joints, they may be failing and will take the tranny with them.

 

Well, I had the Disco (a 2002) serviced this week, and they noted the "trans/transaxle fluid" as full and the rear differential as "n/a".
I've had the truck for about 18 months, and have no idea about the u joints. I'm not really a mechanical type. Never had to deal with these issues before.
It is also making a high-pitched whining noise when I apply the gas, but that stops when I let up. Both issues are somewhat intermittent.

I guess the only thing to do is to take it to a dealer and have it diagnosed, though I am somewhat hesitant to do that. I had an earlier noise that the dealer said was a bad alternator and tried to set me up for a replacement for about $1200. No thanks. I got an alternator for $200 and had it put on for $40. Funny part is, it turned out to be not the alternator, but an idler pulley just below. Got a replacement for $25 (as opposed to $135 from the dealer).
Hence, I'm wary of the dealer.....

 

Then don't take it to the dealer. Nobody in their right mind goes to the dealer unless they have to, there are plenty of good independant shops. If your ildler pulley was bad, your tensioner pulley could be bad to and you should hear it when stopped.
All you need is a wrench to unscrew the upper plug from each axle differential and make sure that there is at least some fluid at the hole. So, how many miles do you have? If over 50k miles I would replace the ujoints in the front driveshaft regardless. Do a search here for "front driveshaft" and read all the posts, you'll get the idea.

 

Take it to a front end shop and have them check the front wheel bearings and ask them to check the fluids in both differentials and the transfer-case while it is in the air.
When your wheel bearings go bad they will make a grinding noise.
As far as the other noise, have them check your belt and belt tensioner.
If it is your wheel bearings ask them if they will install parts if you buy them, most indie shops will. They wanted $400 per hub for my trk, I spent $120 for two rebuild kits form AtlanticBritish and they did the work for $60.