Hi all, new to the forum and to model trains.

I bought a used Santa Fe 8352 Diesel Engine, which was not working. I took apart and cleaned the motor and armature. I was able to clean the copper armature, brushes, and e unit and I was able to get it to move and fire the lights up. However, the vertical engine on forward will only drive 12-14 inches and the motor seems to pop out of gear and revs on high without the train moving anymore. It seems a little better in reverse however does the same after a loop around the track. This is also without pulling any cars.

It seems as if the worm gear is popping out of gear. The power truck is stamped "8250-125".

I noticed that the plastic gear that the drive shaft is attached to also slips and has fallen out. I have pushed this back on.

I tried screwing down the set drew on the plastic brush plate but this did not work. There is no other washers or bearings to adjust or replace.

Any ideas?
Can I rebuild this unit or just look for a new/used power truck to replace this one.

I tried attaching pics but the website says the server is full.

Thanks for any information.