engine "squeak"

I have a couple of Genesis SD70MACs that have a couple hundred hours running time on them. They both run great and pull great but every now and then one of the units lets out a high pitched “squeak” I took the engine home tonight and cleaned and lubed all the moving parts. It helped the problem and the squeak is very quiet now. Any idea how to eradicate it completely?

keep it lubed up…

I have a squeak that has emerged on my Proto 2-8-4 that has me totally stumped… so far. Loco looks and runs absolutely beautifully, and will creep all over the layout, even thru the squeak points, which don’t squeak at crawl speed. I have cleaned and lubed everything I can think of, including tender truck bolsters and axle ends, with no luck. It only does it at two places on one curve (yeah, I know the radius isn’t perfect), but it will not stop.
Quests like this keep things from getting boring.

I’ve had this on a few locos over the years - have you put a drop of oil on each motor bearing? This will often solve the problem. Also worth oiling the worm gear bearings on diesels, as this makes the drivetrain freer to turn. Hope this helps!