2006 Chevy Tahoe Terminology

Hi there, The lifter is a small hydraulic device that eliminates the need to re adjust valve clearances, they are also called lash adjusters, the tappet or more commonly called the rocker is the device that transmits the motion of the cam lift to the valve it pivots so it is called a rocker. Note, in cars with out hydraulic lifters the lifter is solid and the rocker or tappet has a manual micro adjuster to set valve clearances.

A pic of a typical rocker...

mark (mhpautos)