FWIW, I contacted Amsoil technical support last month to confirm which of their greases they recommend for snowmobile suspensions. I received the following prompt response:
Thank you for contacting AMSOIL.
In response to your inquiry, the water resistant grease (GWR) is the best choice for your snowmobile suspension parts.
Thanks again for the opportunity to respond to your concerns. As always, please feel free to contact us again if we can be of further assistance.
The water resistant grease is Amsoil Product Code: GWRCR-EA
My order of the water resistant grease should be delivered today or tomorrow...