Type Designations for Specific Applications

Viscosity or grade designations may be used by other groups or organizations. AGMA are  the  best  example of  such a group, but  the  American Society of  Refrigeration Engineers have set up  viscosity standards and  other  organizations are  contemplating  such  action.

The  manufacturer  of  machinery  often  finds it  necessary  to  provide a  designation of a  lubricant which  has been  found  satisfactory for a specific mechanism. At times  such a  designation may  include  the name  of the  device as  is  the case  with  automatic  transmission fluid, known as ATF. Other  such  types  of  lubricants may be  evident  when  specific  applications  are  considered.  

Designation and recommendation of gear lubricants

While  industrial  gear  lubricants  are  often  marketed  under  trade  names, information  is  always  available  as  to  how  these  products  conform  to  AGMA  numbers . Therefore, little   difficulty occurs   with the designation of this time of gear oils.

However, in  the  case  of automotive  transmission  and  axle  types  of  oils the  marketing  designation  has  not  always  been  clear  and is, in fact, sometimes  misleading. The SAE  Handbook, in  about  1924, started  to  include SAE  viscosity  numbers  for  such  lubricants, and when , in 1951, API approved  definitions  for ‘Regular-Type Gear  Lubricant,’’ ‘Mild  Type  EP  Gear  Lubricant,’’ and  ‘Multipurpose Type  Gear  Lubricant’’ these  terms  were  suggested  for  use  by  SAE. With the  availability  of   improved  EP  gear  oils, as  mentioned  above,  the  API   Lubricating  Committee, in 1957,agreed  that  such  products  should  be  known  as  ‘Multipurpose  Type  Gear  Lubricants (API  Service  GL 4).” Such oils were described as follows:

“This  term  designates  Lubricants  which  have  adequate  load  carrying  ability  and  other   required  properties  to protect  hypoid  gears  in  sustained  high   speed  and /or  high  torque  service  in  modern  high  powered  passenger  cars  and  trucks.  Also  suitable   for  use  in  spiral   bevel  gears, many  transmissions, and  worm  gears  in  some  types  of  service.  Such Lubricants are identified as meeting ‘A.P.I. Service GL4’.’’

The  consumer   of  gear  lubricants  should  bear  in  mind  that   such  products  are  like  other  commodities, in  that , while  a  conscious  organization  may  set  tolerances  for  material   to  be  supplied  under  a  given  designation, some  products  offered  will  barely  meet  the  required  specifications. Therefore, the  purchaser  or  user  of  gear  oils  should   deal  only  with  reputable  firms.