Getting ready for an open house on Sunday, I was cleaning the wheels on my AristoCraft railbus and noticed that the rear axle was slipping/grinding the gear.
I pulled the motor block and pulled it apart to find that the nylon gear had a rounded area removed from where it contacts the worm gear. I went though my geared axles and found that the USA NW-2 uses the same size gear and same length shafts, but the bit was a bit loose about the AristoCraft stub axles.
I put a drop of gorilla glue in the gear where the stub axles sit and assembled it. After the glue expanded a couple hours later, I was able to remove it from where it oozed out along the plain bearings and the bearings spin freely. I reassembled it using a couple of the Kadee shims to push the motor down a bit and secure it against the gear and let is sit overnight.
Today the gear feels nice and tight on the axles and do not spin independantly. We’ll see if it lasts.
