I have a 2001 ( I think) LX Rear deraiuller on my Giant iguana. It has XT shifters if that matters, cables have been on since 2001 as well but I don't think the cables are the problem here.

The barrel adjuster where the cable enters the rear deraiuller has become corroded, it can be turned with pliers but I can't turn it with my fingers anymore. It's basically so hard to turn I can't adjust the deraiuller anymore.

I loosened the cable and sprayed the adjuster with WD40 and other assorted chemicals but it doesn't seem to have loosened it up.

The bike shop says they can fix it (without seeing the bike yet) but I'm wondering if I should just get a new deraiuller online and do it myself.

Anyone seen this before or have a tip? Other than the adjuster the deraiuller still works just fine.

Ben