I should have used shuddering instaed of chattering to avoid any confusion.
Lubing the slip yolk really only applies to the two piece drive shafts. You lube the splined joint between the two pieces.
The Raptor has a one piece drive shaft. So it's a moot point.
What connects the rear diff to the transmission? Isn't there a slip yolk on the rear driveshaft that needs to be lubed?