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5793 Views 23 Replies 8 Participants Last post by  Marauderer
I have just acquired an SD-70 and was test running it today. After about 10 laps around a 250 ft loop pulling 10 cars it started making noises. We took it off the track into the club house and hooked up power to it and both trucks are making gear noises that aren't sounding good. Has anyone else had any problems with their SD-70.
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i have 9 of them, a few are quit a few are noisy, make sure the axle tips are seated in the truck bearing, also you could pop the cover on the motor blocks and look to make sure gears are lubed and meshing with other gears, i had one motor block that was dry from the factory, other wise its new let it run for a while and break in shoudn't have a problem...
Before removing the covers, stuff cardboard or foam between the top of the blocks and the frame to keep the motor blocks from dropping and dislodging the axles and their bushings. Unlike the axle bushings [O] in two axle motor blocks, the main axle bushings < O > in these blocks are rotated 90 degrees, tits up if you’ll pardon the expression. The smaller bushings [O] on the secondary shafts are not.

Keeping the motor blocks from flopping around is very important because there is a drive shaft between the main motor block and the floppy axle. If the shaft drops out of the U-joint, the top cover has to be removed and it’s a real bear to get the shaft back in and have it stay in.
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Thanks Nick and Paul for the input. I will work on it Friday and post the results. From what you are saying Paul inverting the engine affects the gears? If I read it correctly.
To add to what Paul said. Just turning the loco over is fine,no problem. But before you remove the bottom plate on the motor block,wedge something between the motor block and the frame. Other wise when you remove the bottom plate the upper motor block housing can fall away from the axles and bearings.
Paul, just to be sure I understand you, it's the single, "floppy" axle that has the flats of the bearing not parallel the the motor block bottoms, all others are in parallel?

Thanks, Greg
Ok, we checked the gears this morning and found that there were a few stripped. The cause was not installing the square brass/bronze bushing properly on the jack shafts. When the rubber tired wheels were replaced with solid steel wheel they were all installed with the diamond point (tits up) up which on the four axles that it was wrong on after a few laps to warm up and incomnplete tooth contached they stripped. If I can figure out how to attch pictures I will post some but this is not an easy site to post pics on. I am so glad to find the problem and identify the cause which is an easy fix. I also called NorthWest short Line and they said they hadn't made any gears for the SD 70 but If I sent then a geaqr they could make it out of Delron. If I can get them from USA I don't think I will pursue it any farther.
There are two layers of gear shafts when you open the main block of the SD-70.

The bushings on the top set point up , the bushings on the bottom set are parallel to the edge of the block [o]. The bottom cover of the block has triangular indentations ^ that the top bushings fit into. If top bushings are rotated improperly [o], the cover will not close.

I never opened the floppy gearbox, as I was only trying to remove the sliders.
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OK Pictures, I am having a terrible time learning how to put up pictures since the new format. I checked in the section on web questions and still I am falling on my face.

I have posted some pictures in my web space section but still can't make them work. All suggestions are appreciated

< img src="http://1stclass.mylargescale.com/marauderer/BBKB%20RailRoad/Sd%2070%20MAC/DSCF0235.jpg">
Thanks Paul I can make them much smaller or what is the best size to fit and how did you do that?
OK Picture

< img src="http://1stclass.mylargescale.com/marauderer/BBKB%20RailRoad/Sd%2070%20MAC/Sd%2070%20MAC%20II/339632512_wm6GK-M.jpg">
Paul, I got it and I posted on the testing and bugs forum and it worked. Thank you I was really frustrated. I am ordering my parts from USA today and hope they have them in stock. The SD 70 is a really handsome locomotive and will be one of the pillars of my 1:29 railroad loop.
Posted By Paul Norton on 07/27/2008 9:47 PM
Remove < img src=" from the start and replace it with

Most interesting Paul! :confused:

First I wondered how you got the "bracket img bracket" to show up in your post without having to resort to the embedded *asterisk* to keep "my" computer from trying to interpret it as a command? Is it because it is the last thing on the line? How'd you do that? :confused:

THEN, when I started to create this reply (and assumming I might see in the quoted text how you got the text to show), I note that the quoted display of your text shows the photo using the "img src=" encoding... indicating exactly what you said to remove and use the "bracket img bracket" encoding... which seemingly contradicts what you are saying. /DesktopModules/NTForums/themes/mls/emoticons/blink.gif

I was supposed to be a computer guru back in the day many years ago, but this internet stuff just gets sillier and sillier... I just can't quite figure it out anymore/DesktopModules/NTForums/themes/mls/emoticons/w00t.gif
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You are right it should have just showed the dreaded box with the red X.

I think what went wrong with Barry’s post was the space between the opening bracket < and img. A small error like that is what can make writing HTML frustrating. Let’s remove the space and see what happens.

I taught myself HTML by buying the book “Creating Web Pages for Dummies” and writing test code. On our club web site there is a page “Work in Progress” set up just for this purpose.

Our web site also has both WYSIWYG and HTML Editors built in by the service provider editme.com. You can throw plain text in the WYSIWYG Editor; format it using formatting icons; and toggle to the HTML editor to see how it is formatted. I saved examples in an e-mail folder called Templates, and refer to them when I get stuck posting. I now write my web site articles using Word with the HTML tags included. I always feel rushed when I am on-line, and Word has a grammar and spelling checker.
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I know this picture is huge but me being able to post pictures after all this time is also hue. Thanks Paul for the help. This picture was taken along the Rim of the World scenic bypass in Los Angeles County when I was out there a couple of weeks ago. This is the real BNSF and I considered myself fortunate to have seen this train and getting to photogragh it
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Has any one put a Aristo-Craft 3-axle diesel motor block under a USA Trains SD-70 ? Later Bruce
Bruce, what advantages would the AC truck have over the USA truck?? IMWTK?? I am really interested in why you would want to do that as my USA trucks are very smooth and have great power when assembled properly. Hehehe!!

I ordered the intermediate axles w/gears today from USA and they were only $4.95/ea. I needed four but ordered six so I would have a couple of spares. I will probably never use them. My friend has a USA GP-40-2 and they use the same intermediate axles so I ordered him a set also. The are not the same truck as the SD 70. The wheels are smaller and the main axles are closer together because of that.
This is off topic but. Can one of you tell me are the wheels on the usat sd70mac 40" wheels or are they drastically under sized like the rest of usat's engines.
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