I just bought a 2004 disc 4.6l and it vibrates at times. My guess is the driveshaft and ujoint. I'm very new with discos and I need all the help I can get. For one, is there a way to tell that is indeed the problem? Also, I found one that is greaseable . Do I need to replace the ball as well? Is replacing straight forward? Thanks for any help.

 

If it’s original, you should replace it immediately no matter what. The design flaw is that the driveshaft is right next to a catalytic converter and over time, the heat cooks the grease and shaft goes boom, wreaking all sorts of havoc.

To check, simply get under it and wiggle around. That’s not fool proof, but is a start.

So if you’ve found a greasable one (Tom Woods, or GBR are the go to brands a lot of people use- I’m partial to GBR) swap it in there. It should have zerk fittings for the the U joint at each end and the slip yoke. Grease at ever oil change (at least that’s what I do).

Replacement is just 4 bolts at each end if memory serves. You may need to jack the car up or roll it forward or backward a few inches to get access to all of them at each end. Pretty straight forward.

 

And you can R&R the driveshaft without special tools, but the socket that’s made for it makes life a lot easier. They’re not terribly expensive.

 

Since you have a 2004, you can remove the front driveshaft and lock the CDL. That way you can drive the truck with the front shaft removed to confirm that it was the source of the vibration.