Old Athearn GP38-2 how to install drive shaft?

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My "new" ebay Athearn GP38-2 data sheet says Rev 05-03. First time on the track, front truck wheels will not turn. Reason: front truck drive shaft not installed, lying on frame next to motor. It is not possible for the shaft to come out or to go back in without moving the worm gear and bearings, or the whole truck. The worm housing seems to snap on, but it really looks like trying to snap it off will require special tooling, and even then could very well break it.

The drive shaft has hex on the motor end and a ball with knobs on the truck end.

If anyone can tell me the answer I would really appreciate it.


Well-Known Member
The worm gear housing snaps off readily by sliding a small flat screwdriver under one of the tabs on the bottom of the housing. Come in from the front and work around. Those housings are rather durable and should not break, at least I have never had one break. While I have never needed one, I'm sure Athearn could provide a new one and I'm sure plenty of forum members here have some extras around somewhere. As best as I can tell, they have used the same housing for at least 40 years.
Dear santafewillie -- it was just as you said. This time I was not afraid of it and the worm housing popped off intact. I figured out how to connect the drive shaft and got it all back together. The loco runs smoothly and quietly. My grandkids in Greenwood, IN like to watch the Indiana RR GP38s go by just a little way from their house. Now they will have one to run on their bedroom layout. Thank you for sharing your knowledge and confidence with me.

Ed Berners


Well-Known Member
These older Athearn engines are pretty durable pieces of equipment. The mechanisms are pretty proven over the years. If you have any other issues don't hesitate to ask. Most of us forum members have years of experience working on these things and there is probably no issue we haven't seen.
I think I have found a home here, thanks to you, willie.

The Athearn loco runs so well I want to keep it that way, so now I'm going to put in the five-wire system that I ran across somewhere. If I can do that, then on to DCC and sound. Thanks again for getting me started.


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