I have a spectrum DCC equipted sd45. When I run the loco, it will stall and then it will catch on and run and then stall. When it stalls, though, i can still hear the motor running. Has anyone had problems like this before?
Yes, mine was dc but it happened. I removed the shell and found that if I removed the drive shafts and put them back in, It worked.
I would run the loco without the shell, try to observe what is happening. If the drive shafts are the problem, Bachmann service might be able to supply them. If not you may have to send it in for repair or replacement.
Looking at the parts diagram, there are at least a dozen different places for a potential drive problem. You need to start at the motor and work your down to the trucks. Disassembly appears to be straight forward, but I would be reluctant to take the trucks apart to replace the final drive and idler gears.
I don't want to pre-assume your abilities to fix things, only you can decide on how you want to proceed.
Good luck