o rings and gaskets

[robeward]

I am going to change outdrive fluid tomorrow. There is a drain, vent and dip stick. all have o rings/seals of course. should they be replaced each time or only if appear to be in rough shape?

if need to be replaced is it possible to buy a variety pack and just match up or is there an actual part number I need to get?

volvo 290 duo prop

 

[skydiveD30571]

Replaced each time. Atleast that is the general stand for most people. I went by the mindset of "they look ok so I'll keep them on" for a couple years, finally replaced them last year, and this is the first year I haven't had any trace of water in the lube. For the price, it's hard to argue against it. I've always just ordered them by separate part number (SX-A drive).