I need to find a gear lubricant that will work properly at 450 degrees F.  I have found several lubricants with flash points and scuffing temperatures well above this temperature, but have also been told by an engineer at a ball bearing manufacturing company that there are no lubricants that work well at this temperature.  Pitch line velocity is 1400 fpm.  Contact pressures are as allowed by AGMA standards with 1.5 service factor.  The gearbox is small, so unit cost is not a problem.  The oil will also lubricate ball bearings in the gearbox.  Any suggestions?

Here is the home page for Krytox from Dupont. Look at the new L series materials. I know this works on bearings but am not sure about shear at temperature. Fill out their questionnaire.

I'll try get you the information on another material that we use on molten salt pump bearings.


http://exceed.dupont.com/Krytox/webpub.nsf/Pages/index....

Amsoil has "Synthetic HT Series High Temperature Lubricating Oils...Thermally and oxidatively stable up to 500°F...can also be used for a variety of applications, such as gears and bearings..." http://www.amsoil.com/products/industrial/ht.htm
 
If the oil doesn't work out, a moly-filled grease may work: "Perma Moly EP #1 has an operating temperature of -10ºF to 600ºF." Flash point is 510°F.  Don't know whether the low temp. viscosity will be a problem; check it out:
http://www.schaefferoil.com/data/260.html