I've got 2 different Lionel 1980's era diesels with very little run time with a similar problem. The steel pin that holds the idler gear between the two drive gears on the outside of the truck assemblies of a 3 axle (FM Trainmaster) & 2 axle (F-3) like to walk out from the truck until the pin contacts the sideframe of the truck, allowing the idler gear to become loose fitting & sometimes lock up the drive train. These pins show no noticible wear, and the locos are practicaly brand new. Was this a fit issue from the factory? I'm guessing that this pin should be press fit, or lock-tighted in there, but it'a so loose you can pull it right out of it's hole with your fingernails. What's up with that?
Those two models have different gear set-ups, the FM has a single idler with one axle being directly powered by the motor, while the F3 has a jack shaft arrangement with a drive gear & two idlers.
The dowel pins used for idlers in either design are press fit, so a tiny dab of Lock-Tite will work in either case.
Rob
What is the issue? Is this a common manufacturing problem from that time period or what? These two are practically straight out of the box brand new.
I have dozens of these locos and have never had this problem.
Yep, two different locos, same era production, new in the box, slightly different designs, same goofy popping' out idler gear jamming' problem.
When one of those that you own freezes in place after skidding to a stop & sits there buzzing at you with the lights on, remember me & you'll know what to look for.
Please clarify the part that is causing the problem. Is it the shaft in the center of the truck, with a worm wheel (gear) in the center to match the armature, and a gear on one end to drive the wheels through a pair of idler gears?
In Lionel's supplement 1-9 on their repair documents web site, page 362 shows the FM Trainmaster truck frame. Part # 2321-75 is the Dowel Pin holding the idler gear. This pin does not fit tight & walks itself out, allowing it's idler gear to loosen & occasionally jam up the drive gears. This pin comes out so far that it touches the side frame. It is so loose you can easily grab it & slide it in & out. Seems to me like it should be press fit into it's hole, or lock tighted in? Was just wondering if its a common problem & what other people are doing about it, but it sounds like it's not an issue with many other units from this timeline.
Here's the page it's on. The F-3 truck assembly drawing is also on there showing the similar idler gear dowel. Like I say both units, although slightly different, do the same thing on at least one pin/ idler.
http://www.lionel.com/media/supplements/Supplement1to9/1Complete.pdf
Thank you for clarifying th problem you are seeing. I don't think those dowel pins have any sort of head on them, so I am not clear on how the dowel pin moving outward would allow the idler gear to wobble and jam. Aren't the gears trapped by the flanges on the wheels?If the pin is moving out so far that it wiggles too much, I'd echo the suggestion to use a little locktite to hold it in place.I'd use the low strength, removeable formula, after using mineral spirits to carefully clean the pin and hole.Not trying to give you a hard time, just trying to understand what is going on.
I was trying to describe a 2328-78 shaft assembly because I've noticed that a number of the engines with this part need attention because there can be binding due to either the #2328-82 worm wheel (gear) or the 8010-116 drive gear rubbing on the truck block and binding. But that is a different issue.
Basically, as the dowel pin moves out of its hole during running, it wiggles at the outer end, the idler gear teeth no longer mesh properly with the drive gears, it moves just oh, so slightly off center, everything slams up solid & stops moving. You can then push the pin all the way back in with a small flat screwdriver, just touch the idler gear with a fingertip to free it up while wiggling the drive wheels with your thumb, everything resets, frees up, and works again for about 5 minutes until it does it again.
I went with the lock tight idea, we'll see what happens. I wonder if these pins were supposed to be pressed fit in their hole or what? The other pins on the other trucks on the same 2 problem locos are tight in their holes. I'd guess either the holes were drilled too big, the pins are too small, or they forgot to put some locktight on them at the factory? This whole problem should not be happening on a practically new loco.
I suggest that you disassemble the truck and put the loctite in from the inside. Otherwise you must might loctite the gear to the shaft. 680 loctite dries hard and is very strong.
I cleaned the hole from the outside with electrical tuner cleaner on a thinned down cotton swab, then applied lock tight with a thin piece of wire to the inside surface of the hole in the frame, dropped the pin back in and she's been running ever since. Just waiting for it to happen again at this point, monitoring the situation.
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