I just got a rewritten or updated Atlas II guide from AA that includes new lubrication recommendations.

Quote from the book:

"Before operating your Atlas, please fill with the recommended gear lubricant (Torco MTF). If you are unable to find this lubricant, one of the following synthetic oils can be substitute for the Torco brand: Castrol Syntec 5w-50, Valvoline 20w-50 or Mobil 1 Synthetic 15w-50. We have found these synthetic lubricants to work well in the Atlas."