I just bought a NEW SD40-2 from a reputable ebay retailer. it seems the motor have issue to start spinning due to a poor contact with the brush at a specific location. if I spin the motor manually, it will start running no problem. If it stopped at that location, it will have issue to start again. other locations seems to be fine. I thought this is an issue without breaking in. So I let it run for about 1 hour with variable speeds and frequent starts/stops (all manual work). this only gives little-to-no improvement. What would be my next step to resolve this problem? conductive lubrication to the brush? If I need to open the motor, what would be the proper way opening it without damage? mailing it back for repair/replacement is not going to be cost effective. but if there is no other ways to repair it myself, does anyone know how long it is going to take? which I will mail a GP35 back for repair as well. (Super noisy engine, I own more than 10 Bachmann engines, so, i know what noisy means, but this one is super noisy even after break-in. this GP35 also had similar problem with motor starting, but the problem went away after break-in.) with 40% of my bachmann engines having problems right out of the box (I purchases 5 in the last 2 months), I dont know whether I am going to purchase another Bachmann or not.

I bought a digital commander set with a GP40 inside. it makes some kind of groaning noise at low speed. the noise goes away (or covered by the track noise) when speed goes up. I tried to follow the instructions from this topic to open the shell and see what is wrong inside, but no luck with prying off the gas tank. I already slightly damaged the edges on the plastic shell and gas tank, and still the gas tank will not come off. Am I doing something wrong here? And, Bachmann, why not using screws?

I bought a digital commander set with a GP40 inside. it makes the same groaning noise at low speed. tried to take off the shell and do some inspections but no luck.