gear case grinding

[mclaunchpad]

My lower unit has been making that ugly grinding noise When I put her in forward. I adjusted the shift cable and that helped for a month. Now it is slipping gear when I go to plane off. I have minimized use of the boat. Any advice on how to determine if I should replace or repair unit myself. I should have stated it is a 1996 250 yamaha salt water series. Thanks for any info.
P.S. This site is great !

[jb123]

if you are able to put in gear, f & r, at idle no probs, then i would have to suggest replace the 33c gear cable as it sounds like its on its way out. unhook it, run it on a hose and manually engage gears, check if you have a solid rev and fwd.

[mclaunchpad]

It goes in gear just with alot of grinding when I go in forward

[mclaunchpad]

it also slips forward gear under load I will Try your sugestion tonight thanks