Gears Stripped - What to do?

Mr. Black 

Go to Lionel's website and they have a parts breakdown of your locomotive and the parts available that you can order.   Hope this helps.

Allan O

Before fearing the worst, have you checked to see if some piece of debris has been picked up and become lodged in the mechanism?

Another possibility is that a traction tyre has swollen or become damaged and is catching on the brake shoes. Or even that the sideframe is slightly misplaced and causing the brake shoe to contact a tyre.

Any of these can cause the truck to seize and emit terrible sounds and vibrations.

As 400e wrote, if there is a stripped gear, it is probably the worm wheel (gear). Remove the truck, and detach the top plate (part # 39). Inspect part #35. If the gear on the center of the shaft looks worn, replace that entire part. I think the postwar equivalent part costs about $7.00. I imagine the cost of the modern era one would be similar. 

These gears will strip due to lack of lubrication (experience speaking here).  Once you replace it, be sure to squeeze a generous amount of grease into the grease well.  You would also be wise to check it at intervals (dependent on level of use) and add grease as necessary.  I'll also note that this particular style of truck assembly makes it very easy to replace a stripped gear.  The gear in your engine is likely nylon and you can purchase metal replacements.  The early Lionel TMCC GP-9's all had this same style of truck with nylon gears.  I ended up replacing all of mine with the metal worm gear.

After experiencing stripped worm gears on a couple of my engines, I began keeping a maintenance log so I can track how long it has been since I last added grease, oiled wheels, cleaned brushes and so on.

Curt

The OP said it was a stripped F-7.  The diagram is of the much different FT.  Before he goes ordering parts, we should figure our which it is.

Jon

21973 is a FT diesel, so the diagram posted is correct. I am betting on this engine it is not the axle worm wheel that is stripped, but the worm gear on the motor shaft. If just the motor is replaced, it will chew up the gear again. There is a design flaw with these locomotives where the motor and worm wheel do not align correctly. The motor must be shimmed so it leans about 4 or 5 degrees to align correctly. In this instance I would recommend taking it to a local auth. Lionel repair shop, or send it to me, unless you have some patience for tinkering!

Chuck

www.only3rail.com

Thanks for everyone's input, I'll take it apart and look at it and post pictures.  I'm sorry but I said F7 and it is an FT. Chuck, I'll get back to you.

Here are pics, sorry for the quality. Using the iPod.

Motor one shows signs of wearing.  The worm wheel looks ok. 

Above- Worm Wheel 2

Above: Worm Wheel 1

Above: Motor 2

Above: Motor 2

Above Motor 1 - shiny and a bit worn.

Motor 1 - Again a little worn.

BEEN THERE   i suggest you listen to chuck.  replace both the motor and the gear or else you will be doing it again in a short time   i you arnt comfortable yourself,  send it to chuck as he is right  there is some kind of an alignment problem with some of these diesels.

Hmmmm...plastic/nylon drive gears...seems to ring a bell. Didn't we have a discussion about the durability of plastic vs metal drive gears recently??

BTW, I have one of the first twin motored FT's produced by Lionel. I noticed after running it for a brief period of time, the can motors became extremely hot. So I sent it back to Lionel for warranty work. Their fix was to tilt the motor away from the worm on the drive shaft, as mentioned above, by inserting a small ball bearing between the motor and truck thus giving the motor a slight tilt.

I can't comment on the overall durability because after the repair, I only ran it for a short time and then packed it away. I think it still ran a little on the hot side but not as bad as it did before "the fix".

I always felt that Lionel should have used a lower gear ratio on these FT's where the can motor made more revolutions per revolution of the wheels. At the high gear ratio the small can motors had a hard time moving the train so you had to compensate by increasing the voltage and current thus forcing the motors to run hot. This coupled with the "tight" worm gear mesh caused problems. I believe the worm drive gear on my FT was brass (or more likely bronze) so it wasn't a metal vs plastic issue. It was just a poor design.  

Ken

I have found that engineering plastic worm gears last the longest.  A good gear bronze is almost as good, and brass is destined to fail within six hours of first operation, lubrication notwithstanding.

We have motor failures - the bronze bearings holding the armature wear, and the brushes will start to contact things they are not supposed to contact.  A drop of oil on the bearings once a year helps.

opinion.

I have had drive gears in Lionel, Williams

and Kline fail for all of the above.

Im with Curt. log everything and chck and rechck

and keep em greased.

I even had a brand new williams loco come through

with NO grease in the well and the gear failed after

only one train show.

Hotbox, if you look at the pictures, you will see that a metal gear is chewed beyond use. Ran into this during the **** rush, used a postwar gear and shaft to replace the modern era parts, worked well. The motors had a spacer between the motor and the truck, it apparently moved the motor gear, which is tapered, too far from the driven gear, on both trucks. 

Sorry to hear you had trouble with a new Williams engine! Was it a Williams by Bachmann? WBB as most people call them have quality issues with the circuit boards.

I never had a Williams motor or gear give me any problem, usually the circuit board goes bad first if anything does.

Had an older Lionel Santa Fe diesel engine strip the gear or motor gear shaft, was told I had to replace the truck assembly and armature, cost was too expensive for me. So I bought another engine.

Lee F.