Motor shaft vertical movement/excessive play.

If it was an open frame/Pullmor motor you could add thrust washers to the armature shaft to stop the vertical movement. You would have to replace the can motor to correct the issue, as they are non serviceable.

You can try swapping the trucks and see if the issue follows the truck or not. That way you know which component is at fault.

As a long-time tinkerer (not to be confused with "craftsman", as some are here), may I ask:

- How "severe" is severe, in actual measurement? Some vertical play is normal (from the worm/spur gear interaction, as you mentioned), and some cab components are placed very close to flywheels at the factory, intentionally or not. I have had a diesel or two do a little "flywheel scrape" in one direction or the other - even both. If it is not damaging anything (like cutting wires) or does not make a truly awful noise, it will probably wear away.

- I'm sure that you have looked, but is the truck attachment screw tight and are the smaller screws that attach the motor to the truck snugged down? This is assuming that the historically typical construction methods were used. Either of these issues can also cause binding, especially in one direction or the other.

- Remove the offending motor from the truck and see if the worm looks worn - it certainly should not be. Take out both motors and compare their shaft play. Maybe one motor is off-spec.

D500 posted:

As a long-time tinkerer (not to be confused with "craftsman", as some are here), may I ask:

- How "severe" is severe, in actual measurement? Some vertical play is normal (from the worm/spur gear interaction, as you mentioned), and some cab components are placed very close to flywheels at the factory, intentionally or not. I have had a diesel or two do a little "flywheel scrape" in one direction or the other - even both. If it is not damaging anything (like cutting wires) or does not make a truly awful noise, it will probably wear away.

- I'm sure that you have looked, but is the truck attachment screw tight and are the smaller screws that attach the motor to the truck snugged down? This is assuming that the historically typical construction methods were used. Either of these issues can also cause binding, especially in one direction or the other.

- Remove the offending motor from the truck and see if the worm looks worn - it certainly should not be. Take out both motors and compare their shaft play. Maybe one motor is off-spec.

I mentioned that the flywheel hits the LED board inside the roof of the cab when in reverse and there are to circles carved into the flywheel visible in the pic. I would say the play was a good 3/16 of an inch.

Hi,Are you sure it's the armature and not the whole motor?  I've seen where the screws that hold the motor to the mount(shown in your pic) loosen up allowing the motor to lift.

Doug

trnluvr posted:

Hi,Are you sure it's the armature and not the whole motor?  I've seen where the screws that hold the motor to the mount(shown in your pic) loosen up allowing the motor to lift.

Doug

Yes, I'm sure it's just the shaft/armature.

It's not normal to have 3/16" play in a can motor, I looked at half a dozen in my parts box, all have less than 1/8" play.  IMO, the motor is defective, it shouldn't have nearly that much play.  There's nothing in the truck design to keep it from moving the full excursion, so the only sure is replacing the motor.

gunrunnerjohn posted:

It's not normal to have 3/16" play in a can motor, I looked at half a dozen in my parts box, all have less than 1/8" play.  IMO, the motor is defective, it shouldn't have nearly that much play.  There's nothing in the truck design to keep it from moving the full excursion, so the only sure is replacing the motor.

Thanks John, I'll get one ordered.