Just as a side thought. I had problems with my monkey starting to make a lot of noise when going up and down. I didn't grease the threaded shaft, I used synthetic grease to lube the straight shiny shaft it rides on, (without threads). Problem solved. Before, my monkey would try and drop the ball on the upper play field , but it would be short and then the ball would drop down to the lower play field about every third time. After the lubrication of the straight shaft, no more noise, and the ball drops up top without problems, and it stays on the upper play field.
Good luck.