Mechanical Problem with Atlas SD60 - need advice

[Maletrain]

I brought a club loco home to attempt some speed matching, but quickly had a mechanical binding problem.  Looking for some advice on how to proceed.

The loco is an Atlas SD60 (Soo Line #6053) with an NCE N14A1 Rev A decoder.  It ran fine at the club for years, and seemed to run fine at home when first put on the track.  It was packaged well for the trip and not dropped.  But, it suddenly jammed up and would not move on the track at home. 

I took the shell off and did find some brown fluffy "stuff" in the opening in the top of one of the gear towers, which blew out easily.  Now the loco runs in reverse only, and makes a clicking sound with the rear truck.  it is somewhat hesitant in reverse, but jams immediately in forward -- won't go more than about 1/2 turn of the motor in forward before it jams.  Will not move at all after jamming until run in in reverse a bit.  Then it will barely start to run in forward before jamming again.

I am not familiar with taking these locos apart, but I guess that is my next step.  Advice on how to take it apart and what to look for would be appreciated.

[u18b]

My first guess is grit in the gears.

Thoroughly clean the trucks.

[Maletrain]

Grit is my first guess, too.  I am just wondering how to get into the trucks.  It looks like I need to take the split frame apart.  But, maybe the bottom panels come off without taking the frame apart.  Trying not to force anything I don't understand, and also trying not to take apart anything that I don't need to take apart to get a the gears.

[u18b]

Not necessarily.

Is it the new mechanism with wires from the trucks which plug into the frame?

If there are no wires on the trucks then it is the older mechanism.
Pull the shell.
Then unscrew the end screw partially and gently wiggle the truck out on that end.

[rodsup9000]

It ran fine at the club for years, and seemed to run fine at home when first put on the track.  It was packaged well for the trip and not dropped.  But, it suddenly jammed up and would not move on the track at home. 

    Sounds like it's ready for maintenance (motor bearings oiled, gears cleaned of any harden grease, and trucks taken apart and axle points and axle cups cleaned well) anyway.

 These Atlas loco's are very easy to take apart. Just take pictures as you go.  Here's a parts break down of the SD 60
https://download.atlasrr.com/PartsPDF/NScale/N%20SD-60%20DIESEL%20LOCO%20CHINA.pdf

[CR4100]

I had a high mileage that was noisy even after tearing the trucks apart and cleaning. I replaced the trucks with new ones and it runs great again. T

rucks are available from Atlas here: https://shop.atlasrr.com/p-3653-n-sd-60-truck-assembly.aspx You will have to unsolder the wires if you're fitting them to a version with the pick up strips.

[bman]

When you get the trucks off the mechanism look at the truck towers. Just below the top that seats in the mechanism there should be 2 little pegs on the sides of the gear case. When assembled the bottom of the mechanism rests on these pegs. If they are broken off the truck sits too far into the worm causing it to sound like a coffee grinder and run erratically. I've run across this a few times with used SD 50/60 locos from Atlas. 

[Steveruger45]

When you get the trucks off the mechanism look at the truck towers. Just below the top that seats in the mechanism there should be 2 little pegs on the sides of the gear case. When assembled the bottom of the mechanism rests on these pegs. If they are broken off the truck sits too far into the worm causing it to sound like a coffee grinder and run erratically. I've run across this a few times with used SD 50/60 locos from Atlas. 

Yes.  This.  Had similar on Intermountain SD40s too.

[Maletrain]

Thanks for all of the suggestions.  I have the original "1998" frame without the wires, so I will be able to work from the drawings that were provided by bman and rodsup9000 and follow the advice from u18b (and maybe from CR4100 if I need a new truck).  That is the kind of help that makes this forum the best!

I will post the results when I get into the mechanism.  Not sure when the will happen, because the forecast of impending deep snow has just complicated my schedule for the rest of the week.  I might not be able to get to this now until I am snowed-in.  This is something I don't want to be rushed or interrupted while doing.

[Maletrain]

Well, I am finally getting to this after the snow and ice complicated my non-train life.

The truck is off, and a lot of fine hairy stuff has been removed from the gears.  It looks to have been relubed, before, with a light blue grease that is still quite soft (and excessive).  But, it still does not turn without locking up.

I need to get further into the gears.  How do I get the truck frame off the gear case? 

[rodsup9000]

4 little latches on the bottom of the truck. I use pointed tweezers to unlock the latches

[CR4100]

It's also worth noting that the wheel spacing of the three axle truck is not even. The contact strips must go back into the side they came from or else the side frames will not snap back on.

[Maletrain]

OK, It's back together and running smoothly in both directions.  And the support pins on the sides of the truck towers are all intact.

Thanks to everybody who provided guidance.  It was prompt as well as just what I needed.

The odd thing is that I still don't know what was causing the problem.  When I got the rear truck apart, I noted 2 small flake-like pieces of light brown material in the gear area of the rear-most wheel, and though "AHA. got it!"  But, those apparently were not the problem at all.  The problem was something binding the front-most wheel, and only in one direction.  After checking all the gear teeth for debris and breakage, and getting a lot of very fine hair-like material our of the gearing all around, I was still getting the same binding action in one direction, only.  I finally tried using tweezers to scrape the sides of the wheel gear where it could touch the housing, and scraped the housing in the same area. That did the trick, but I really did not feel anything come loose when I did the scraping, and I could not see anything on those surfaces before I scraped them.

So, there is still some mystery to the malfunction, but I will take the smooth running as a win - at least while it lasts. 

And, I learned how to take apart and reassemble an Atlas SD (wireless version). 

[rodsup9000]

  Glad to here it's back together and running smoothly