Do you recall what kind of washer is used to hold the rotating plastic disk in place [also shown in the picture]? I lost mine and tried getting one from a hardware store, it did not work at all [the screw becomes loose].

I think there is a special washer that allowed a smooth gear shift motion?

I have been trying all day and I will appreciate your advice very much!

 

I have found out that the washer part number is WJ105001J, will update.
Thanks

 

Found a washer from ACE hardware that works perfect.

 

Sounds like a frustrating day. Good to hear you found a suitable washer.

I've added 'RESOLVED' to your thread title to help anyone searching for the solution to this problem in future.

Graham