What is the proper oil for gearbox on a 2QM15?

[Bob Graham]

The original owner's manual says on page 29 paragraph 2-2 to add the same oil used in the engine to the gear case. The Yanmar 2QM15 service manual states on page 12-6 to use an automatic transmission fluid. I have also read that Herth gear boxes use ATF type-2 fluid.

 

[Bob Clark]

Dexron transmission fluid!

I have a copy of a letter dated May 12, 1981 from K. Furumiya, assistant manager of marketing for Yanmar. He said "To get more accuracy in the engagement for the clutch, our recommended lubrication oil for the "QM" series, i.e., 3QM30, 2QM20 and 2QM15, was changed to transmission fluid." This letter was included in the Southern Cross Owners Association newsletter dated November, 1981. The former owner of my Southern Cross 31 (and its 2QM20) used Shell Dexron transmission fluid for years. Me too! It is one of the types listed in the 2QM20/3QM30 Service manual I bought from Torresen, on page 13-6.