A volunteer group I am in has 2 Annies that get a lot of run time at a public garden railroad. They are about a year old and now have a similar problem. The knurled section on the rear bearings has moved in the frame and has machined the plastic. This is primarily on the rear (driven) axle and more severe on the right hand side (looking forward). They run okay, but the axles wobble quite a bit. The rest of the drive and siderods are fine. Does anybody have a fix for this problem?

If replacement of the drive is the only option; how do we keep it from happening again. These are Version 6 chassis.