T&T: Spring Lube & Filter Change Questions

[Garrett Lambert]

I'm about to do my first oil and filter change on the boat: Cummins 220 main
with Twin Disc transmission, and a Northen Lights / Lugger 6 kva generator.
An OilEx exchange system is hooked into the Cummins and the transmission,
but not the Lugger.

I had thought to hire a local mechanic to do the first round while I watched
and learned, but when two cost estimates were provided at Cdn$600 and $1200
respectively, I put that idea right to bed. I purchased the engine oil and
filters (oil, and both primary and secondary fuel) today, but hope someone
can answer a couple of questions:

1) if I change the primary fuel filters on the 2 engines, will I have to
re-prime as was the case with my old Lehman?

2) Twin Disc told me the transmission uses either straight 30 or 40 weight
engine depending on operating temperature, but wasn't able to say which for
my combo. Does any of you know?

Cheers, Garrett