Or look thru the screen at backside of engine.
While turning engine over to see if driveshaft turns with engine at engine end.
There is another pin at the other end of driveshaft with a rag joint then another pin.
Seems like the pin in shaft at engine is the one that breaks first.
If it is the engine end pin, you need to fix the coupler on the engine that pin rides in.
The pin slot becomes "L" shaped.
You can fill weld the worn portion of slot and grind it back to what it looked like new.
