If you have a typical GM starter with an overrunning clutch, the clutch is slipping. A no-load test on the starter won't find that condition. The clutch can be replaced, but you should also replace the shifting fork- depending on the starter. If the starter is the Bendix drive type, usually not a GM application, the Bendix spring is broken, or the anchor bolt has come out. I would suggest taking the starter to a rebuilder to have the work done. You will get a better job that includes replacing brushes, bushings and thrust pad, and turning the commutator.
Harvester
