450b h/l/n/r problem please help

[Lfd270ben]

Help I have have a 1976 ( I believe) with dry clutches and powershift it has been acting up.
symptoms:
When I try to change the gear (1-4) most the time it wont let me and then it wont find any gear?
Low works when I can Find a gear but sometimes Reverse wont engage and it seems like high isn't fully engaging?
when it is cold it seems to not be having as many problems but the longer im on it the more problematic it is? and sometimes it performs flawlessly?
Solutions?
any help would be awesome.
Thanks,
Ben