MTH SD45 with locking gear/truck

Steven, have those gears been lubricated with a light oil including their hubs?

Larry

also sometimes a small rock or pebble gets stuck between the gears that came from your road bed and stick in the gears clearing that out usually fixes the problems of binding gears or sometimes the wheel shift on the axle and to much free paly causes them to jam as well!

good luck let us k now how you make out!

Alan

repair technician posted:

also sometimes a small rock or pebble gets stuck between the gears that came from your road bed and stick in the gears clearing that out usually fixes the problems of binding gears or sometimes the wheel shift on the axle and to much free paly causes them to jam as well!

good luck let us k now how you make out!

Alan

There is definitely nothing caught in the gear.

Steve,

The likely answer, regardless of the root cause of the problem is a new truck block. You have too much play somewhere, causing the gears to un-mesh and jam. Call Midge in parts. The block comes with all 3 axles, so tell her you need a 3 rail 3 axle power truck block. You will have to transfer your existing pickup roller, side frames, pilot and coupler over to the new block. Watch that you do not cross thread the screws for attaching the frames.

Chris

LVHR

Double check..... an unbelievable small piece of anything in the gears could cause this.

clem k

I agree.  I have rebuilt these transmissions from one end to the other, including new axles and axle bearings.  The only time we have ever had a spur gear lock up it was a small rock.

We get several years of daily running between axle gear changes.  The worm gets replaced every three axle gear changes, and I have only had to do axles and bearings once, over 20 years of museum running.  Never replaced a truck block or a spur gear.  

Well, maybe inspect the teeth closely on both? I've never seen it but just maybe there's a defect in one of the gears?

As far as being too loose, I haven't seen that be a problem yet either. Doesn't guarantee that it couldn't happen though I guess?

Interesting. We'd really need better close up pictures to help from a distance! If you think that it's not right, there maybe nothing else to do but take it in.

Didn't someone post awhile back about pushing those rivots in a smidge to tighten up the slop?

What I do when I get one with jammed gears, is disassemble the loco, remove the truck block, soak it in mineral spirits to remove grease, and use a retired dental pick to clean the space between each gear's tooth. If this doesn't work, Lehighline is right, a new truck block is inorder. But try the cleaning first. If the center axle is the one driven by the motor, you might have a motor problem, that is why you take it apart and pull out the motor. Be sure to clean the motor gear thoroughly also.