i dont think they lr do manuals for later boxes as they stopped factory training in unit rebuilding years ago ,but earlier manual will do for what you need layout is identical,i had to rebuild a l322 transfer box the other day for our local dealer as they had no idea or info on how it was built or worked,if you do have a go yourself you wont want a rebuild kit just front gasket,filter ,sump seal ,oil pump housing seal 4 x seal for oilway to clutches and any parts that are faulty ,the parts are cheaper bought separately and not from zf ,i can give you suppliers numbers if needed,you generally find unless box has been severely overheated everything bar your problem will be perfect,nearly every one ive rebuilt has really only needed one way clutch and one or two of front clutches replacing,whereas before they were put on diesels just clutch A