Saildrive Oil Change

[Tranona]

If the 130 originally used the hypoid type stuff and they are now suggesting to use engine oil is there a lot of difference between them?
The reason I ask is that I originally had a 120 leg which had to have the lower portion changed to the 130 leg with the split anode and the different gearing.
I presume in effect I have the 130 leg and the oil should be 15/40?

No. The 130 did not use EP (Extreme pressure, for use in some gearboxes and axles). It used ATF, which is what I expect your leg was filled with when new. The recommendation is to change to engine oil, but the consensus seems to be that this should only be done by draining all the ATF out rather than just extracting from the tube, which leaves a residue of ATF in the leg.