gp9 drive noise

[thetramp]

I took the front trucks off the GP9, took them apart and I could not see any broken teeth or chips. I had another truck from I think a life like locomotive. I took that apart and the gears looked the same size when I placed them together. I than swapped the gears from the life like to my athearn and they were a match. I put the athearn back together, greased it up an put it on the tracks. I still have a slight hum but not anything close to what it was before. It must be the athearm hum that I always hear about. I will let it run for a while to break in the new gears and will report back. Thanks for the info given me. I really appreciate all the help as I have been out of model railroading for more than 30 years and pulled my trains out of the attic about 6 months ago. I know I have missed a lot of needed knowledge in those years and hope to catch up. Also, I am a little clumsy with my hands and I also have some arthritis in them but I am determined to learn as much as I can and fix what I can.