Iceland! Thats pretty cool....welcome. Im gonna provide what little knowledge I have to help out, but man....you gonna have to give us some pics and tech data on your ride!
Ebay will be you best place for supply only if you know what your doing. I cant see replacing the worn pieces will be a difficult task, but ive never rebuilt an eaton, only centrifugal.
Also on ebay are plenty of used eaton m90's. Maybe a swap out with a good rebuilt will be easier. Dont forget them pics man!!! Thanks for showing up!