i have an 88, back in high school (about 11-12 years back) it always worked, never had a problem. as it started getting older, sometimes it would go in 4 wheel and sometimes not. my dad took off the shift motor and cleaned all the electrical connections one day, and then it worked for a few years with no problems. this past year, we got about 10 inches of snow and it would go in 4H, but not 4L. it was ok tho, cause i didnt really need the 4L for the snow.
that being said, i just bought a manual 1350 from another TRS member for $100 so i dont have to deal with it not working anymore. and one more thing, a shift motor for these cases is ~$100 depending on where you go (and it'll eventually go bad again too)
go with the manual