And yes, the bushings look the same. The axle ones are at 45° and the ones for the idlers are at 0°.
I have rebuilt a whole bunch of USA 6 wheel power trucks.
While usually it’s a popped apart slip shaft, as you found out, not always.
You replaced the axle gear in the pivot ends?
There was something…the way the driveshaft connected…bushing worn…I can’t remember…keep having visions of Botch Shays in pieces, Botch plugs and wiring falling apart.
You can pull the bottom big cover, both those axles, hold the articulated end firm and apply power and watch.
My guess is the front u-joint is hitting a housing part or screw…but that’s a guess, as I don’t have one here.
I Might be able to dig up a PA, but not tonight.
If the bottom or top cover of the articulated axle isn’t seated or fitted correctly, it can hit the u-joint.
TOC
Thanks for all the input. At least I know that it’s not common. Since it’s affecting both of my trucks, it must be something unique to my rebuild. I will investigate further.
Eric
I’m thinking that a quick test would be to swap the 2 axles from your B unit into one of the noisy ones.
I assume all that you changed was the 2 axles, not the intermediate gears or the floppy one.
Greg
p.s. dumb question, did you count the teeth on the old gears and the new gears?
I changed all three axles, but not the intermediate gears.
Ahh!
Were the axles in the floppy units “cracked” also?
Based on your videos, I strongly suspect something amiss in the universal drive, add that to what TOC said about it coming apart, sure seems the most likely.
I’ve never disassembled that part, other than removing the axles very carefully and re-gauging.
Greg
No cracks. I just replaced them all for good measure. I don’t think I touched the drive shaft in the process, but I’ll tear it down again.
It seems it’s pretty buried down there, can you take some pictures when you get down inside it?
Thanks, Greg
If you listen to the noise on the trailing powered box car that I purchased used you will slightly hear what sounded like a death rattle which turned out to be.
A crappy picture of the the culprit. One tooth missing from the drive gear on the pilot axle.
Only my limited “personal” experience.
Check out this link /vignette ON LSC …https://www.largescalecentral.com/forums/topic/22514/cvrr-ocs/view/post_id/387680
Please post your resolution Eric
Thanks,
Rooz
I will post the resolution. I don’t think it’s a missing gear tooth, as the gears are brand new, and made of delrin.
I’m really focused on my layout at the moment, as it’s starting to get colder here. I probably won’t dig into this for a few weeks.
It is though, along the line I was going with my request to swap back the originals one by one.
Clearly a missing tooth will give you the noise. (thank you Rooster)
Perhaps the custom gears are not quite the same dimensions, or have some variation in tooth spacing.
Greg
How often does the gears need to be lubricated. My locos do not run very often, I spend most of the time building.
Ron, once you have sufficient grease inside, pretty close to never, I’ve never seen one without lubrication there.
BUT
You need to lube the axles, there are plain bronze bearings, I prefer heavy gear oil.
You need to lube the journals where the axle tips ride, because that is where all the weight of the loco rests, and they get dirty and gritty. I recommend a good moly grease, and you need to replace when they start to wear oblong.
I do have what might be helpful information on my site: https://elmassian.com/index.php/large-scale-train-main-page/motive-power-mods-aamp-tips/usat-motive-power/diesel-motor-block-tips
Greg
Greg,
I’m experimenting with using ball bearings on my USAT sideframes. I’m battery powered, so I don’t need to use the conductive sideframes. I’m hoping that these ball bearings will work better.
Eric, and progress/resolution on your issue?
Greg
No, this is on the back burner until it snows and I can’t play outside.
Thanks Eric, really curious as to what the mystery is.
Greg