What is a centering ball?
 

While I have my transmission out I figured I would replace my u-joints but looking on the forum I see that I also need to replace a "centering ball". I looked on rave and couldn't find out what that is. What is this and where is this located? If I'm replacing u-joints I'd like to do a full replacement of the assembly. I bought four Precision 344 u-joints. What is the part number for this centering ball and how many do I need?

Thanks

Give me a moment, I'll walk out to the shop and see if I can find the part number. You can get it at a local O'Reilly or someplace.

And you only need one.

Precision #617 is what you need

Thanks a lot. Quickest response time ever. I have no idea what it looks like so could you tell me where this goes?

It's going to be located inside of the knuckle part of your driveshaft on the side that is connecting to your transfer case. Like below-

http://i42.tinypic.com/121df6d.jpg

It's basically just a round metal ball. Once you get that part of the driveshaft apart you can easily get to it.

You can kind of see it in this pic-

http://i41.tinypic.com/2ewffgl.jpg

Street Wolf thanks so much for taking the time to find that part number and also the awesome pics of it. I do have one more question. I'm starting to feel really dumb but does this centering ball only exist on Disco II and later? I have a '97 Disco I and I do not have that added joint where the ball rests in your photo.

Lol, I believe so. Certainly saves you some work at least. :D

Only the D2s use the double cardon joint in the front driveshaft. Your 97 will have 3 u-joints, 2 in the front driveshaft and 1 in the rear. At the rear pinion it has a roto-flex coupler that you should probably replace since you're doing the u-joints anyway.