Huh??? Anyway.... Your GM dealer sells a grease specifically for this purpose. I would recommend using it, although I'm sure others have used different products. Here's the procedure from GNTTYPE.org:
White lithium grease-Lubriplate brand-is the most popular.
Graphite compound is best.
Don't lube the last 6 inches near the speedometer head, it can work it's way into the speedo.
Hi,
Sorry for the blurry comment before. Graphite lube, as you would use in a lock,is my favorite.I have had NO luck separating the two cables, however.As a consequence, I have been unable to lube the lower cable.