Not really any new parts available for the old hyster units. The brake band can be relined. You can purchase lining materials online. But I would do an online search for brake and clutch relining services. Many places do this work. Otherwise for gears and shafts, that would be used parts, possibly from tractor salvage, dismantling companies. Bearings most likely available new. Other members have more experience with Bearings. But you just need the number off the Bearing, and do internet search for number, or call Bearing suppliers. If you plan to use your winch alot, keep your eye out for a complete winch as a backup parts unit.
Really easy to find the bearings and seals. The exception to this might be the giant seal that goes around the drum, depending on the model. The shafts and gears you will need a parts winch or a machine shop.
"i reject your reality and substitute my own" - adam savage. i suspect my final words maybe "well shit, that didnt work"
instead of perfection some times we just have to accept practicality
the winch on our machine used felt as a seal on the drum. we bought some from the bearing joint we got the bearings from. note ours isnt a hyster winch