I have some rattling noise and vibrations coming from under/front area of the vehicle, it happens when I let off the gas and it's usually much louder while driving on the expressway. So I crawled under my Discovery (2004), tapped around with a screwdriver and the only thing that is close to the noise is the front drive shaft.

The cap on the front part of the shaft can be moved back and forth, I didn't take it off all the way, YET. The rod feels very solid, no movement while the vehicle is parked at least

Anyone have any idea what this could be?

I attached some close shots of my drive shaft. The last two photos I got from the net.

 

From the looks of it i think you might need a new drive shaft. Your u joints might be going bad. When you let off the gas there is less tension on the shaft an therefore the u joint has room to move and make noise if they are worn. I had similar noise when my front shaft was failing. i doubt your joints have been serviced plus i can only see 1 service point which looks like a hi pressure service point on the shaft. You can try rebuild your shaft if thats the culprit or buy a new one.

FYI this is what my u joint looked like when it made noise.

 

Did you try rotating the drive shaft to see if there is movement in the u-joints? Tapping it won't tell you much. Also check the u-joints for grease fittings, if it has them grease them.

 

I haven't done that yet. I wil get the car on flat surface, get the tension off of the drive shaft and try rotating it.

 

I also think its the U joints but need to be certain before I start removing parts. Can I just replace my joints without replacing my entire drive shaft? Do they come off easy?

Looks like you did TONS of work to your Discovery, I checked out your photos. GOOD JOB man.

 

Look at this thread for the horror of what can happen when your joints give.
https://landroverforums.com/forum/di...mission-28607/

then search this forum for driveshaft and u joints for the literally 100's of threads on the topic. It's the most common failure on these trucks.

Personally, I'd stop driving it until I could fix it if that was my Disco.

 

That is not a stock D2 front drive shaft, inspect the ujoints for zerk fittings, and honestly I have an aftermarket drive shaft that looks identical to that one & it's a piece of crap. I had to remove it off my 02 Black D2 and the previous owner had just put it on 3 months earlier, and from what I can tell the center ball is trashed. I had a chirp and bad vibe. Stuck in a good rebuilt unit and problem went away.

So try lubing it, if that doesn't help replace the entire unit before it destroys your transmission.

 

I will take the drive shaft off this weekend and inspect it. I haven't been driving the Disco for a few months now. Its not my primary transportation...

 

I plan on removing the front drive shaft this weekend to inspect it. Do you think I could take the car around the block with the front drive shaft removed just to make sure the noise and vibes are gone? I need to be sure 100% that this is the root of my problem.

 

If you enage the center locking diff then yep you can run around the block to test it.