Hi @axum
If there's a buzzing or humming sound coming from the motor then it seems like a problem with a motor winding.
There are two windings in the motor, a start and a main winding.
Both windings are connected when the motor is first switched on, so as to produce enough magnetic flux to overcome the inertia of the motor in the idle condition allowing it to start to rotate.
When the motor gets up to speed there's an internal centrifugal switch that operates to disconnect the start winding, so that the motor can run on the main winding only.
The start winding has only thin wires so you don't want them to burn out. The main winding has thicker wires so it can run for long periods without overheating.
Since it doesn't continue to rotate when you manually spin the tub it sounds like the main winding is faulty.
Check the motor wiring connections of the motor itself e.g. loose etc.
Unfortunately you can't use an Ohmmeter to test the individual windings because they're connected in parallel via the centrifugal switch, which may be buried somewhere inside the motor.
Although looking at the wiring diagram if you disconnect the harness wires from the motor and connect the Ohmmeter between terminals 5M and 4M if all was good you should read between 1.2-1.8 Ohms i.e. the specs show the motor windings are between 2.4-3.6 Ohms each so since they're in parallel, the resistance is 1/2. If you measure 2.4-3.6 Ohms a winding is faulty. Do this with the power disconnected from the dryer
If the motor is faulty the part number is 279827. (supplier examples only)
Search online using the part number only to find suppliers that suit you best.