Lionel Shay 6-38066 gear issue

I am not familiar with the exact construction of this loco, and I do not own one, but the "fine in one direction and rough in the other" problem - plus an apparent complete, temporary disengagement of the motor/drivetrain reminds me of a couple of diesel's behavior. One turned out to be a loose truck (the Big Screw underneath the truck was loose, allowing the spur and worm gears to disengage - in one direction), and the other was a loose motor (on the truck, held on by 2 small screws) - which ran fine in one direction but would stutter and bind in the other - again the worm and spur gears were disengaging.

Both were screwdriver fixes. Check your entire drivetrain's mounting situation. Also, the outside Shay gears work like the real ones - see if anything has fouled them or if any are seemingly not running true.

A lot of moving parts on the Shay.  I had to shim the axles of my 2-Truck Legacy one to get the gears to mesh properly.  I have a TMCC 3-Truck model, but so far it runs fine.

KENJR,

I have that shay, try using a small bladed straight screw driver and make sure both screws holding crankshaft cylinder rod block to engine is tight as they tend to lossen up after awhile resulting in your issue, a little lock tight seems to cure this issue.

If that's not the issue try this,there are 2 gears one within the main cylinder crankshaft block that meshes with another within boiler area. 

If you can jumper wire to hot roller and a ground on engine while upside down on work bench apply power while applying pressure to gear  area see if it will run in forward.

This is a weak area as no bearing support to hold these gears in place.

Good luck hope this helps you.

I just had a similar problem with a Western Maryland 3 truck Shay.  Turns out the helical gear with worm was the problem, part number 6SP-8022-101. (Item number 42 on the Lionel parts diagram for your 6-38066).  The worm gear became loose on the shaft and would not drive the rest of the drive train.  It's kind of easy to check.  Take the bottom cover off and you can lift that part out and check it mechanically in your hands by turning the gear and worm to see if they are loose...after you clean all the grease off of it! 

I just ordered a replacement part for my Shay.  Maybe you have the same problem.

Thanks for the replies. Getting ready to go out of town for a few weeks. I will spend some time with this when I return.

I am waiting to see if the current shay release in 2017 catalog uses same crankshaft assembly as the 6-38066 as I tried pinning the metal shaft to counterweight all was well until mister lets tweak the counter weights so both are lined up  well I should have left it alone as it was only out of alignment by a 1\16" and I broke the counterweight where the pin was!

I contacted lionel but a vague response as to if the new 2017 release would use the same crankshaft assembly for the first TMCC release.

so it sits on my repair counter as a reminder of my dumb move!!

Well after a bit of time away from trains, I got back to looking at the Shay problem.  One issue I found was the front axle seems to come out of the hole on the gear side and makes it bind up. I looked to see if the were any adjustments and could not find anything. There could be other issues as well, but decided this is likely more complex than I can fix.  Any one out there that works on this type mechanical issue?  All of the electronics work fine.

Ken

Kenjr posted:

I recently purchased this Shay w/TMCC. Unit had almost no run time. I took the time to lubricate before putting on track loop with 072 curves. At first it ran a little rough (in TMCC mode) so I let it run for 30 minutes at a medium speed. This seemed to smooth things out quite a bit. I was able to run at a slower speed but still seemed to want to stall at certain points both on straight and curve. Decided to put away for night and check the next day. When I went to start it moving it stopped abruptly but I could hear the motor/gear still running.  I stopped it immediately. In reverse the engine seems to run fine. In forward if I give it a push to get a little speed it will run but will lurch/stall at slow speed.  I did take the bottom cover off to see if I could detect any problems, but nothing seemed wrong. I am guessing somewhere in this gear train it is binding, but I could not determine where.  Is there anyone that has had this issue and solved it?  Again this happens even on straights.

Ken

I have the Cass Shay from the K-Line take-over and had issues with the shaft pulling out and the gear spinning.  Lionel worked on it and it still had issues, talked to their tech who suggested using lock-tight on it and waiting a day so far it has been fine.  It definitely doesn't like track under 0-54 and maybe what caused the problem.  I think if you run it with the gears on the inside of curves it will run and not have as many issues.  Once the gear comes loose it doesn't seem to matter if its on straight or curved track, its still a problem.  Not sure if that's what your issue is but it did work on mine.