I’ve been using Straight SAE 30 in my drive. But lately I’ve been doing some research on the oils used.. One Volvo publication says on the single props engine oil is to be used on Everything up to The SP-A2 where it states “same as engine or SAE 90”. All afterwards models are all SAE 90. Another Volvo publication says everything after and including the single prop 290 uses SAE 90?? Then some people say SAE 30 is good while others recommend that SAE 40 is better. My drive is a mix of parts.. 270 Upper gearbox with the lower unit replaced with an SP-A1 model. So what truly is the best drive oil for this setup?? Also would a zinc additive to the motor oil help to minimize wear? Something like Lucas Zinc plus?
Thanks in advance!
Thanks in advance!