Starter problems

I have a 1994 Ford Ranger with a 2.3L 4cyl. 5 spd. With 153, 00 miles. The problem is it won't start, just click. The battery terminals have been cleaned, and the battery checked with a hydrometer and load test. The starter was removed and taken to autozone and checked ok, was reinstalled and all connections cleaned, still same click. Voltage at starter is 12 volts and when in start postion solenoid wire has 12 volts. I'm stumped. All connections are clean and wires look in good condition. Help please.

Just a update. I took starter back off and they retested still showed good. This time I mentioned that they were testing with out it being under load they agreed gave me a new rebuilt starter and it works now Thanks for the answer.