What type of Grease for the Gears on a 1998 EMD Switch Engine

I did a forum search for "Atlas SW8" and found dozens of replies, yet none talked specifically about gears and the material from which they're made. 

On this forum there is no agreement as to which gear grease is best.  However, having monitored the forum for 11 years there is a notable number of modelers whose favorite is Red and Tacky.

I've been using Red-N-Tacky for years, no complaints.  IMO, having some grease on the gears is far more important than the exact brand/type of grease you use.

@J. Motts posted:

Good Morning Everyone,
I was working on an old Atlas SW-8(?) and removed the cover off of the bottom of the trucks as I wanted to grease the gears.  What I found was some sort of tan colored grease all over the place but none really on the gears, I'm not sure if they are plastic or metal.  Does anyone have any idea as to what types of gears these are and since they are in an enclosed case, what type of grease can I use, I have a white lithium that I feel would work best but I also have some Red and Tacky that I use for gears that are always uncovered, the type that are against the wheels.  It holds really well if you take your time applying it.

Any help would be greatly appreciated.  Have a terrific day.

Tan colored grease is most likely a Lithium grease. Many types of grease are a mix of compounds into a suspension. I say suspension because what happens over time and with heat and age, the oil which is the primary lubricant leaches and evaporates off, leaving the other stuff behind. Often that left behind becomes very hard and the exact opposite of a lubricant.

Again most grease is some form of oil lubricant, mixed with "thickening agents" and then other wear prevention additive compounds.

So yes, I would recommend scraping out as much as possible old dried Lithium white grease (sometimes tan) and replace with a modern grease like red-n-tacky.