Starter Motor Problems

[banana_socks]

Starter motor in my car has decided to stop working. Turning the key just gets a rapid series of clicks, but no engine movement.
Battery is fine. I grabbed another from a working car to test without improvement.
Tried directly shorting the solenoid wire to the positive terminal, no difference.
Tried a set of jumper cables directly to the terminal and starter body, no difference.

Figured it just must be screwed, so pulled it out this arvo. However sitting on the ground it will work fine, extends and spins freely when powered. Took it apart, cleaned the contact surfaces, but everything looked fine. Chucked it back in the car, but still no luck.

Is it possible that it actually is buggered but can still function with no load? Any other tests I can do to locate the problem? Pretty lost atm.

[ta22fan]

solenoid shot?

[maccac__1590]

bad earth?? to solenoid/entire starter? or the hold in windings in the solenoid is open circuit?