I have not heard of the low temperature requirement. The operator's manual specifies "cylinder oil soda soap grease." It seems from previous discussions on this forum and the Early Ford V8 forum that John Deere Corn Head Grease is one of the modern greases that is closest to that old cylinder oil soda soap grease (which is no longer made) so that's what I and many others use. Because this grease is 0 grade and is thixotropic (thins when agitated) it has properties similar to grease with a low melting temperature as you are looking for. The advantage is that it does not have to heat to thin, it thins just by being agitated so it is recommended for -30° to 330° F operating temperatures.
See it demonstrated here:
https://www.youtube.com/watch?v=UEwk_sYP6A8
Get it here:
http://www.greenpartstore.com/John-D...-AN102562.html or any John Deere store.