There's a kit with a rubber plunger and bolt through it (from what I remember). The grease needs to be worked in. There's actually an older 6 page TSB outlining the whole procedure. The kit is about $10-$12 from the dealer.

 

If anyone's interested, check out this thread:
https://ls1tech.com/forums/showthrea...=1#post2894447
In post # 8 there's a link to a DIY Intermediate Shaft Maintenance that walks through the whole procedure