I don't have the manual but if I recall there's several pivot points on the shift linkage going to the forks. Sounds like if you could get the boot off the shifter for the top ones and crawl underneath for the bottom ones that a reall liberal spray of silicone lube would do the trick... ? I had an old Jeep 4 speed that was so stiff in cold weather that sometimes when 4-wheeling I'd have push the shifter into granny gear with my foot (attribute to 38 year old trans, with 38 years of wear and tear and gunk and funk!)