Aristocraft SD45 Modifications & Repair page:









Gear-box noise: 

As I first reported in 2004 about my fix on, if your SD-45 (or other 3 axle Aristocraft engine) runs choppy or seems to have a lot of gearbox noise, you may have one or more motors binding due to the U shaped power transfer strips pushing them out of alignment.

The U shaped power transfer strips that route power from the top circuit board to the + and - motor power leads on the motors can create downward pressure on the power lead side of the motors as the strips are pushed down into the motor block as the block is screwed down to the truck frame/bolster.  This downward pressure forces the motor ends out of alignment with the gearboxes and causes them to push/bind against the inside of the inside of the gearbox worm gear.  



First, flip the engine upside down and only remove the bottom shell casing of the motor block. DO NOT remove the motor block from the engine. (note, mine in the photos below is out of the engine, but is still installed in the truck frame and is solid against the circuit board above which is the key to all this.)

Simply use the soldering iron with this type of tip till you soften the solder on each terminal. Be sure to apply some pressure down on the tab of motor block power lead to push it back into place.

Here is a video to illustrate the before and after results.  It shows how the stress on the end of the motor from the U power strips is negatively impacting the motor driveline alignment.

Notice the center gear box movement before and after the solder is loosened.  - 27mb - 13mb - 2mb


The root cause of the problem is likely due to the fact the motor blocks are assembled outside of the engine (as opposed to installed in the engine) at the factory, then installed afterwards.  If the U shaped power transfer strips are not perfectly tight down against the top of the motor block they will be pushed down into the block (as it's pressed against the above power transfer circuit board) causing the out of alignment problem with the motors which results in binding and noisy operation. 


Please note:  If your engine exhibits this problem it will not get better by trying to run it to break it in.  The root problem needs to be fixed in order for the symptoms to go away.






(Note the last two show a comparison between a noisy and quiet gear-box.)


  The original location for these files is gone so please use these below to access Bob B's videos.

Note:  For these videos you will likely need to right click on the link and "Save As" the file to your

computer and then play them

Dash 9 gear-box problem video #1 (679 KB)  

                                   Dash 9 gear-box problem video #2 (586 KB)

                                   Dash 9 gear-box problem video #3 (340 KB)

                                   Dash 9 gear-box problem video #4 (187 KB)

                                   Dash 9 gear-box problem video #5 (512 KB)

                                   Dash 9 gear-box problem video #6 (278 KB)

                                   Dash 9 gear-box problem video #7 Slow-speed pass-lurching (5 MB)

                                   Dash 9 gear-box problem video #8 Startup and Rev (5 MB)

                                   Dash 9 gear-box problem video #9 Motor Throttle up and down (5 MB)

                                   Dash 9 gear-box problem video #10 Repaired gear-box (553 KB)

                                   Dash 9 gear-box problem video #11 Loud/defective gear-box (5 MB)

                                   Dash 9 gear-box problem video #12 Quiet gear-box (4 MB)






Drive train (Gearbox) failures

If you get a good amount of run time on your engine you may encounter this issue where either a gearbox fails or the entire drive-train fails to operate. 


The failure will be because the plastic axle gear or plastic worm gear strips in one or more of the gearboxes.  If this occurs that drive-wheel will no longer spin with the rest of the wheels. 


If this happens to your engine, you will need to to either replace the gearbox or send the drive-train in to Aristocraft for replacement.  Aristocraft engines have a 5 year warranty and will replace it for free if still under warranty.




Example of drive train/gearbox failure on an E-8:  (Same motor block as the SD-45)










Inexpensive add-on weights: 

Instead of paying $42.00 (MSRP- ART29514) for a pair of 1lb weights (which used to be free), I've decided to make my own for about $2.00 each. (weights ~1lb 3oz) 

Screws if you need them can be purchased from Ace Hardware and are a 4mm screw with a .70 thread pitch.






Sealing the Aristocraft smoke unit fluid reservoir tank to prevent leaks: 

I've found most of the Aristocraft smoke units leak around the inside wall when fluid is added.  To keep this from happening, I run a bead of superglue along the outside corner of the inside wall to seal it.  Once sealed it won't leak anymore.  I usually let it sit overnight to fully dry before reassembling. 

Before sealing

Before sealing






Return to Garden Railroad Modification page.


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