grease fitting on drive shaft

[dennismhamm]

i was greasing the u joints on the drive shaft and noticed this one on the shaft and was wondering what it greased? also there was a plastic nut that was loose on the shaft and notice it had threads so i screwed it back tight. was it ok to do this?

[96 Wideglide]

Looks like the zerk that greases the slip yoke. This allows your driveshaft to get shorter and longer, as your susspension moves.

[wa8yxm]

Very hard to see either ZERK or plastic nut but I'm with Wideglide. Greases the slip joint

[Mr_D]

Yep, all the zerks AND the slip joint.