I don't know how loud your 'squeel' is, though here's my experience with WCS94:
WCS94 was one of my first pins. My initial impression of the spinning soccer ball noise was that the gears were disintegrating and that I'd need to replace the motor or gearbox mechanism.
I went ahead and ordered a new mechanism and installed it. Before putting the platform on the spindle, I tested the motor. Ran fine. Nice and quiet. I then added the metal disc and tightened it with the set screw. Again, a power-up resulted in a nice and quiet rotation.
Finally, I added the rubber 'ball' and it sounded just like what I started with.
In the end, and after comparing my WCS94 to others in the area, I learned that the spinning soccer ball is just plain noisy.
Sounds like you might have some play or a gear missing a tooth in the gearbox.
http://www.marcospecialties.com/pinball-parts/14-7996.1
Or, PM me and I'll cut you a deal on my spare motor.