I just bought a new front driveshaft for my 2003 discovery from Lucky 8.
I have put grease on the 4 obvious fittings but I cant locate the 5th fitting where I use a needle adapter. I guess this 5th fitting allows one to grease the yoke (?) or the thing that is about the size of a golf ball

 

I don't think the shaft that you bought has fifth zerk,,
The fifth one is usually the one for centering ball, (golf ball as you said),,
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But you might be able to use a needle type thing to force some grease into centering ball from the side of it,)

 

Thanks for the input. I was afraid this might be the case.