# GP-40 Gearbox



## rocketrider (May 6, 2008)

I have heard of some gearbox issues with the GP-40. I have had 3 locomotives, 6 trucks with failures so far but I have 12 GP-40's so maybe more to come?? I have several U25B's with no issues would it be feasible to convert the GP-40's to the U25B power block??


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## Stan Cedarleaf (Jan 2, 2008)

Ralph, Ed Headington posted that he converted his GP40 to U25 trucks and they work very well. When I had seen his posts, I converted my GP40 with excellent results. He and I are both running under battery power and experienced a significant increase in run time.

Ed used the current ball bearing trucks and I experimented with a set of the older non ball bearing trucks. They gave equal performance and pulling power. 

The posts and reports are on the Aristo Craft forum.


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## Greg Elmassian (Jan 3, 2008)

The issues with the GP-40 are not the gearbox. It's the same gearbox used on all the newer Aristo diesels. The only drive problems have been a few with motors that drew too much current (a couple have basically burned out). The GP40 motors are unique to the GP40, Aristo has the spare motors in stock. 

I would not worry, since not everyone has problems, and spares are in stock. 

Regards, Greg


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## markoles (Jan 2, 2008)

removed comment.


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## eheading (Jan 5, 2008)

Ralph, as Stan said, he and I have had excellent results using the U25 motorblocks on the GP40. The actual motorblock is a direct replacement with the GP40 block. The only thing is that the side rails are different, the GP40 being a later EMD design. With the ball bearing U25 trucks, what I did was cut off the tabs on the GP40 side rails and bonded them to the side of the U25 motorblock. I took pictures of the "before" and "after", and there is no visible difference. And as Stan said, our run times with batteries almost doubled with the change.

I will say that I actually experienced no problems with my original GP40 motorblocks. I was just concerned because the significantly bigger motor drew significantly more current than the older motorblocks do. In addition I found that my ability to pull cars was not diminished with the smaller electrical motors. Here in Florida, especially in the summer, I experienced polyfuses blowing with 25-28 cars. The same engine with the U25 motorblocks will pull the same number of cars, because the lower current draw does not seem to affect the polyfuses.

Ed


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## aceinspp (Jan 2, 2008)

Ralph: Yep most of the gear failures have been in the 6 axle trucks non in the GP40. I have 4 GP40s and run the heck out of them. As long as you do not over tax the pulling of the loco they will be trouble free. Later RJD


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## rocketrider (May 6, 2008)

I typically only pull around 25 cars with 2 GP-40's and my layout is basically flat. Navin is supposed to fix the trucks,I have had 3 failures so far in the past 3 weeks. I want to try the conversion for my battery loop. How about the electral connections??


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## Stan Cedarleaf (Jan 2, 2008)

Ralph... My GP40 was converted over 2 years ago to QSI using the gwire receiver. I power it with a battery in a trailing car. Just flipped the track/battery switch to battery and away she went.

That's after the install of all the electronix in the locomotive. Basically, it was plug and play.


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## Greg Elmassian (Jan 3, 2008)

As with any Aristo loco, double check that the battery switch indeed disconnects the battery from the wheels. There are some that do not, and there are some that only disconnect "one side" of the track contacts. 

Regards, Greg


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## chaingun (Jan 4, 2008)

OK here is my 2 cents,
I bought 2 Geeps from the first run and have picked up 4 more sense then. The first 2 came with bad drive train noise which got worse with use. I finally tore them down and found the worm gear in various stages of striping on 2 boxes on one unit and one box on the second. I was not willing to go without my Geeps for any length of time so I bought new boxes rather than ship them back to AC. This solved the problem so far but I have noticed one of my later 4 starting to make noise and I have no idea which run it is out of.
As to the power issue, I have found that the Geeps use way more power/amps than any other 4 axle units I have (AC or USA). I do not get near the battery life with the AC units and have more than once blown a 10 amp fuse on the 27mghz TE I use in a trailing car with 3 Geeps and a 40+ car drag. I will say it was a heavy consist with USA tank cars and weighted LGB modern tankers. Also I live in an extremely hot area (120 + on some days and I run in 100 + temps a lot) so that might be a factor in the battery performance / power draw.
I love my Geeps and even with the drive train & power issue I will continue to use the OEM blocks because they pull like ****.
Best, Ted


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## chaingun (Jan 4, 2008)

?? I don't now what that stuff is at the top of my post - maybe cause I did it in MS Word and pasted it. OH well you get the idea. 
Ted


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## Ted Doskaris (Oct 7, 2008)

Ted (chaingun),

As to "... that stuff is at the top of my post - maybe cause I did it in MS Word and pasted it..."
Yes, as I also discovered, it is because the "What You See Is What You Get" (WYSIWYG) editor used by MLS also includes what you don't see is what you get, too!
If you use a more fundamental editor (e.g. Word Pad, Jarte) to off-line compose your material (as I did here) it will work without showing that formatting info. when pasting your text. 

As to the GP40 power consumption problems,

I currently have 9 Aristo GP40s and had one, thus far, with two failed motors.
I use track power and do notice rapid carbon (and perhaps copper oxide) deposits buildup on the rail heads, too. (Noticeable electrical arcing.)

See the article that I wrote awhile ago with the following self explanatory title:
"Aristo GP40 problems - Smoking motors & Debilitated wheels!" 

I hope this is of help,
-Ted Doskaris


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## rocketrider (May 6, 2008)

I had another failure of the gearbox, with another GP-40.

I did find a set of GE trucks and wm going to try the swap, should alos make the unit more compatable with my U-25-B. Apparantly the GE trucks are out of stock and hard to find.


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## SteveC (Jan 2, 2008)

Posted By chaingun on 31 Jul 2010 12:40 PM 
?? I don't now what that stuff is at the top of my post - maybe cause I did it in MS Word and pasted it. OH well you get the idea. {snip...}[/i] If you're going to be pasting content from MS/Word into the MLS Full Featured editor and you're a 1st Class member then use the 'Paste' button







located on the editor's tool-bar.










After the drop-down menu displays select and click the 'Paste From Word' menu item.


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## Greg Elmassian (Jan 3, 2008)

I'd sure like to see the failed gearboxes, the Aristo units are pretty heavy duty. 

I wonder if the "bad gear noise" is the tipoff? Noise is normally a misalignment between the motor and the gearboxes. Normally this should not affect the gears, BUT, if the hex shaft from the motor slips in the hex drive in the gearbox, that would explain everything. 

I HAVE seen this before. 

Regards, Greg


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## aceinspp (Jan 2, 2008)

The GE truck as you call them are used in a variety of AC locos. RS3, RDC, Doodlebug. You should be able to get replacement. So far I've have not had a gear problem with my GP 40s so you diffidently have a problem in the truck. Some have fmade noise but I have never experience a failure with them. Same for some of the 6 Axle bricks that make noise but most of that is due to the motor not properly seating in the housing correctly but it has not cause any failures as of yet for me. Later RJD


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