Help! Rear Six Wheels Want Pull

[damonlee22]

I have a Bachmann HO Diesel SD40-2 DCC Equipped BNSF #1692... I noticed it began to run slowly forward, but will not run at all in reverse... All the lights work, but rear six wheels do not pull or operate! Any Ideas?

[bobwrgt]

Check the drive shaft coupling where it connects to the truck worn gear. If it is loose it will slip on the shaft. Sometimes they are cracked. Replace it or a small drop of superglue inside the center will hold. Also check the connection to the motor.

Bob

[Stephen D. Richards]

Take the shell off and run the powered chassis on the layout.  Watch what happens to the front and rear truck!  That should gives us a good bit more info.  Stephen

[damonlee22]

Rear drive shaft isn't turning at all, neither forward or reverse... Going forward only the front truck is pulling, but in reverse neither will pull. Checked electrical connection, and they are good. Beginning to think it might be the DCC board.

[Jerrys HO]

Sounds like a drive shaft popped out of place. Make sure the shaft is properly seated into the motor shaft. You may have to loosen the motor or trucks to do this. If the front truck is responding to the commands and the rear is not it is not the decoder as the decoder only tells the motor to go either forward or reverse and it sounds like yours is trying with only the front trucks. Dig further and you may find what is binding the rear.

Jerry

[damonlee22]

Okay, removed the rear truck... its completely jammed-up... Gears are binding bad! Looks like it gonna need replacement parts here. I don't understand why this happened, I have kept the gears lightly greased and oiled... idk
Thanks guys for the help.  

[jward]

rake the truck apart and see if you can find what's binding. usually, its' a piece of grit in the gear teeth.

was this locomotive bought new? what has it been run on?

[damonlee22]

Bought new, only a couple months ago... Prob no more than four hours of run time!

[Ken G Price]

Yep, sounds like dirt of some kind stuck in the gears.
If you run the engine with the track on a carpet then it could have carpet fibers or hair in the gears.
It happens and needs to be cleaned when it does. A simple and easy thing to do.

A head band magnifying visor really helps with this.

[richg]

Sounds like you might return it for a replacement or download the diagram and zoom it up enough to see how the worm on the shaft fits to the worm gear and you can see all the spur gears quite nicely. Much better than trying to use the paper copy diagram that comes with the loco.
I just downloaded the diagram and zoomed it. Everything seems to be quite clear.

http://www.bachmanntrains.com/home-usa/dwg/dwgs/H609X_IS001.PDF

Rich

[Jerrys HO]

I have kept the gears lightly greased and oiled..

For an engine only four month's old this should not be needed.

To gain access to the gears you will have to unclip the bottom of the truck plate which will then release the side frames. Make sure the loco is firmly supported upside down for this because as soon as the side frames are removed the wheelsets and gears will fall out. I took a picture so if anything got out of place I would have a visual reference. The reason I know this as I had to replace the wire from the truck to the board.

Jerry

[damonlee22]

IDK... pulled the truck off, removed all the wheel axles, gears, and cleaned. Greased and oiled, replaced the drive shaft... Still want function. May need to dig deeper!

[damonlee22]

Okay, I found the problem fellas... The screw is slipping on the motor shaft. Cleaned it with alcohol and used a little dab of adhesive (I'll be able to get it off if it needs replacing) on the shaft, that's it... Back running like a champ! Thanks for all the help.

[richg]

Okay, I found the problem fellas... The screw is slipping on the motor shaft. Cleaned it with alcohol and used a little dab of adhesive (I'll be able to get it off if it needs replacing) on the shaft, that's it... Back running like a champ! Thanks for all the help.

That is what bobwrgt  suggested in the second response. You must have missed it.

Rich

[jward]

Okay, I found the problem fellas... The screw is slipping on the motor shaft. Cleaned it with alcohol and used a little dab of adhesive (I'll be able to get it off if it needs replacing) on the shaft, that's it... Back running like a champ! Thanks for all the help.

nothing like finding and fixing the problem yourself. experience is the best teacher. if you ever have another problem like this the worm will be the first place you'll look.