trouble with a SD40-2 Burlington Northern item 67007

[rjdiv]

seems like the drive is not meshing properly; if i press down a little on the engine, is seems fine though.  How do you open it up to fix it?

[bapguy]

Remove fuel tank. Should be 2 screws, one on each side diagonal from each other. Remove couplers lift off body. Sounds like an electrical contact problem.     Joe