There are exploded views and servicing instructions for most winches on line, although I never could find one that showed my particular Barient 27s. But if yours says "27" on top but looks nothing like advertised inside, no worries. Although daunting at first, if you can take a winch apart you can put it back together, and if I can, anybody can. Try not to let the 30-year-old races come apart.
I usually tape up a strip of painting paper between the deck and the lifeline to catch any small parts that get loose and bounce off the deck. I have full confidence in my abilities as a klutz! I clean every piece in parts cleaner or paint thinner (not water based) then coat everything with winch grease.
Always have had great results. If you haven't done this before, you might want to take a picture after the drum is removed of all the parts. It could make reassembly easier.
Barients are pretty sturdy and easy to take apart, with less possibility for parts flying everywhere. Still good to be careful.
I did both of my winches "self-taught" just keeping track of what part came off of what... it's not so hard. Agree with Bob above re: taking a picture of it with the drum off before you start disassembling.
For a "parts catcher" I have used the cardboard tray that a case of beer comes it ( for some reason there always seems to be one about). Just cut a hole in it the same size as your winch , drop it on the winch and dissamble.
Currently having all 7 winches in separate boxes in the basement, I will say you they can be reassembled only one way.
with that said allot of pictures were taken just in case.
Currently the boat is in lock down like our state, so they will be there for a while