Sew-Classic is not currently listing Singer grease. There is two types of Singer grease.
The first, with the milky clear to amber grease that resembles petroleum jelly is for the motors.
The second, with the white grease is what Singer uses on their plastic gears. IT IS NOT FOR THE MOTORS.
You might hunt around for old stocks of Singer motor lube or you might do as some have said and use petroleum jelly as lube for the motors. I have read they are so close as to be indistinguishable. Although I do not speak from experience as I have a number of tubes of the Singer motor grease and use those on my Singer motors.
Joe