USA Trains SD40-2 gear problem

[Greg Elmassian]

Yep, and the 2 axle diesels do not go "diamond", they go flat.

 Many people get this mixed up and do the 2 axle ones like the 3 axle and boom, stripped gears.

 Or people start out with the 2 axle locos, and do the 3 axle ones the same, and same result, stripped gears.

I'll never figure out why they did this, but it's true.

Regards, Greg

[got-to-roll]

I repair engines for the Fairplex Garden railroad at the L A county fairgrounds. We run 3 USA SD40-2 engines pulling 30 to 50 cars for 10 hour days all through the fair plus other shows all year. They perform very well with the gears being lubed only once a year. I have never lost an axle gear, but have lost several jack shaft gears that run against the metal worm gear. these are fairly easy to replace with new gear and shaft assemblies from Charlie Roe. they were not very expensive. We did lose some wheel and gear assemblies from 10 years of use or damage and Charlie replaced them quite reasonably. A few burnt out motor blocks due to an accidental derailment not being caught, were replaced at about the price you stated or more, but were reasonable. I don't see the final bills so I can't quote exact costs. The main thing I wanted to point out is that the jack shaft bearings are installed with the edges flat but the axle bearings are installed 90 degrees rotated so the point is down in the slot like diamond. the gears will not mesh right if not installed correctly and strip out right away. Watch when you take off the bottom plate and you will see this. Don't let the spring wire electrical pick ups push up the axle before you get a look at it. Good luck!

[cmrproducts]

Tom

We use the Labell #106 plastic compatible grease.

We usually grease them once a season depending how long we run them during our shows.

They sometimes run for 9 to 12 hours straight.  Something most modelers don't do, run their equipment like that!

 

BOB H - Clarion PA

[Greg Elmassian]

The place they need attention is the tips of the axles, they are not ball bearings. You can lube them without taking anything apart.

I have not experienced needing additional lube on the gears, although I put lube on them when I open the gear boxes.

Regards, Greg

[expresslane400]

Do you need to lube the gears that much? What are you using for gear lube? Could that be part of the problem? I think Ted had a problem with Aristo lube that did not like the plastic.

 

 Tom Thornton

[g. gage]

Howdy Bob; I agree with Greg, for me it started because I’m an SP fan, they doubleheaded (or more) everything even yard switchers. As I stated in an earlier post I have six USA locos and have never had a problem, however I double (up to 18 cars) and triple head (25 cars) all my trains. My railroad is a 450’ loop with a saw tooth profile and 2.5% grades.

 

Have fun, Rob  

 

[cmrproducts]

Greg

The gear boxes have never really been apart!

We just lube them up and that is it.

The non traction tire axle gears look brand new so the replacement wheel set probably is the way to go!

BOB H, Clarion, PA

[Greg Elmassian]

Yep, I love long trains too, just need more locos, ha ha.

By the way, if you think about it, the construction of the unit would require 2 parts, a new "axle" with no gear, made from insulating material, and then a gear to press onto it.

The metal half axles for each side are "live", so they must remain insulated from each other.

So, a new "axle" of plastic, like a tube would need a metal gear, and then the 2 metal half axles would press into it. You would also have to be pretty choosy about the gear material, normally the smaller gear (worm) on the motor is metal, and the larger gear (worm gear) is of softer material. 

I do think the best bet is doubling up your locos.

Is there any possibility that the gearboxes have been incorrectly reassembled? The brass bushings on the axles are in one orientation for 2 axle trucks, and a different one for 3 axle, and I've had plenty of "experts" not have it right.

Regards, Greg

[cmrproducts]

Greg

Yes the Plastic Gear has extream tooth decay (no teeth).

Appeariently (from the above responses) is that we are running these trains under extream circustances.

We run these trains for 12 hours during a Christmas Show and are pulling 30 cars at a time.

I can see that I might be better to get rid of the traction tires and go with 2 or 3 engines to pull the train!

We relube these engines on a regular schedule - so we do not feel that there is a lack of lube problem .

This is why I was hoping for a metal gear replacement for the plastic gear.

We have about 2500 sq ft of display with 7 to 10 trains running during the Christmas season and the engine loss is getting to be too much!

 But the visitors just love the LONG Trains

BOB H - Clarion, PA

[Greg Elmassian]

 Is the gear on the axle really stripped, or do you have "loose half axles". (The metal half axles press into the plastic gear housing and the housing splits)

 You can buy the replacement axle assembly, and get rid of the traction tires.

One problem is that while you get more traction, that axle takes most of the load, and fails first.

Another problem is that people often re-assemble the trucks wrong, placing the brass bushings on the axles in the wrong orientation, and that will destroy your gears in a flash.

You might check my site for tips on USAT motive power.

Regards, Greg

[g. gage]

I agree with Mike; RC Hobbies, Sacramento, CA carries USA wheels/gear both w/traction tire and without, or whole power unit and even power unit w/EMD sideframes.

 

I also seem to recall sometime ago Brian had a fix for the USA gear. I've never had a problem with them myself; I have six USA locos in regular use.

 

Good luck, Rob

 

[Mike Dorsch CJ&M r.r.]

Hi Bob . I just replaced the gears on a gp-38-2 from USA . This unit was used ALOT . The axle that was worn out was the one with the traction tires on it . I called Charles Roe and they sent me out 2 new axles with the bearings , plastic gear , and wheels ready to drop right in for under $10.00 . I'll bet you can do the same for your sd40 . If not i'd bet the gp38 axles would work .I think if you wanted metal replacement gears you might try , I think its called ,and I could be wrong here Northwest Shore something. Hope this helps.

[cmrproducts]

I have several USA Trains SD40-2 engines that have stripped the axle gear.

Anyone have any place to purchase replacement gears

I would prefer not to use the Plastic/Nylon/etc. gear that is factory.

It seems that USA will not sell just the gears and only want to replace the complete trucks assy at $50.00 each.

Oh! and these units are long out of warrenty so replacing the gears is not a problem for us - it is just that no one seems to have any info on gears.

Thanks

BOB H - Clarion, PA