If you are servicing your front knuckles or you have a broken or clicking front birfield joint, this is a GREAT replacement.  These assembleys pull out after you take the spindle off and slide in the differential.  It is greatly recommended that you replace the inner axle seal at the same time.  These parts are NEW not rebuilt or used.  This is the LEFT side (U.S. Drivers) side, the long side.  Fits 79-85 Toyota Pickups with a straight front axle.