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.

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!

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

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.  

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.

The idea behind flywheels was to improve the ability to coast and not have jerky starts and stops. Early in the use of flywheels a lot of motors were 3 pole and the flywheels did help to smooth out the jerks at low speed.

Petroleum-based oils lack both the lubrication performance and oxidation stability of synthetics. Real oil is made up of a mixture of long and short chains of carbon and hydrogen atoms, and under certain conditions the short-chain molecules evaporate, and the unstable molecules oxidize and break down. This leaves a sticky residue which can actually "gum up" the device it was intending to lubricate. Conventional oils also contain varying amounts of impurities, specifically sulfur, waxes, and unstable hydrocarbons which are left behind as residue deposits that might damage plastic parts.

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?