6-83393 Legacy NW2 Drivetrain Sound

dominicpom posted:

Just received my Lionel Legacy Union Pacific NW2 switcher I purchased off Ebay. I would like to know if it is characteristic of these engines that utilize a center can motor with universal joints to power the front and rear trucks to have a kind of a buzzing sound coming from the truck gear assemblies and/or motor. I can't tell if it is the motor or the trucks or the Ujoints. It is not a loud sound and only comes when the engine is at about 50% of its maximum speed. Both trucks were loose when I unboxed it and I tightened them up pretty easily. I really like this engine and probably can live with it as long as it not some sort of warning that a major problem is coming down the road as I run it. Thanks for any help you guys can give me.

I think it's characteristic of the Legacy NW2 and SW7, which share the same chassis. These engines are geared for slow-speed operation as switchers--I believe Dave Olson said 30:1--and when they're in the top half of their speed range, the universal shafts and the gears are really going.

keithL Thanks for that reply. I was hoping that was the case as I really like this engine.

You might want to do a search on the forum about these engines.  You have to add grease to the gear boxes.  There is a bare minimum of grease from the factory.  I added grease to mine and it runs much quieter now. 

rrgeorge posted:

You might want to do a search on the forum about these engines.  You have to add grease to the gear boxes.  There is a bare minimum of grease from the factory.  I added grease to mine and it runs much quieter now. 

Yes, that may be the case, but I think you'll find that even if you have to add grease, there will still be a bit of a whirring sound in the top half of the speed range.

Once the gearbox is properly greased, the sound is much less, but at high speeds, you will still hear the mechanism.  The engine runs at about half the speed of other Legacy engines at the same speed step.

I think it's probably normal.  As stated, it's a pretty high gear ratio.  I just finished up a PS/3 upgrade for a Williams brass steamer, and it has a 44:1 gear ratio.  The motor tops out at around 8,000 RPM at 48 scale MPH, and you can definitely hear the motor noise at that speed.  OTOH, it has great low speed performance.

I lubricated  all the axles and put a little grease on the gears on the sides of the trucks I can get to. Are there any instructions or diagrams on how to take the trucks off and grease the gearbox. It looks like a tricky job and don't want to disturb the sensitive electronics up above.

The easy way is to use the grease port in the bottom of each truck. It’s sealed with a screw. Remove the screw and apply the grease down into the port. It may take a fair amount of grease. I can’t tell you specifically which screw because I’m not in a place where I can look at my own engine, but there’s an older thread about it on the Forum.

dominicpom posted:

Just received my Lionel Legacy Union Pacific NW2 switcher I purchased off Ebay. I would like to know if it is characteristic of these engines that utilize a center can motor with universal joints to power the front and rear trucks to have a kind of a buzzing sound coming from the truck gear assemblies and/or motor. I can't tell if it is the motor or the trucks or the Ujoints. It is not a loud sound and only comes when the engine is at about 50% of its maximum speed. Both trucks were loose when I unboxed it and I tightened them up pretty easily. I really like this engine and probably can live with it as long as it not some sort of warning that a major problem is coming down the road as I run it. Thanks for any help you guys can give me.

Drop the fuel tank and see if the sound persists.  If it does, then the flywheel is rubbing against the fuel tank.  The ones that I serviced,  I had to get my dremel out and shave off some of the metal from the tank to allow proper clearance for the flywheel to spin.  

Blake

Thanks, Blake for that suggestion. I think I am going to check it out. I don't see any screws on the bottom of the engine to release the fuel tank covering the motor, so it looks like the top has to come off and the screws to release the fuel tank are under the circuit boards in the middle of the frame. Is that correct? Thanks for your help.

dominicpom posted:

Thanks, Blake for that suggestion. I think I am going to check it out. I don't see any screws on the bottom of the engine to release the fuel tank covering the motor, so it looks like the top has to come off and the screws to release the fuel tank are under the circuit boards in the middle of the frame. Is that correct? Thanks for your help.

I don’t have one with me to look at,  but you may be correct.  I just remember having to shave down some of the metal from the fuel tank because it was rubbing against the encoder ring/flywheel.  Here is a photo of the fuel tank.  You can see where the factory tried to shave it down,  but evidently didn’t remove enough.