Jeep: 1992 Wrangler YJ Tranny Problem

I have a 1992 Wrangler YJ with 2.5L engine, 5 speed tranny. This morning
as I headed to work all seemed well, until I hit 5th gear. When I shifted in
to 5th gear and let out the clutch there was a terrible grinding noise
coming from the tranny. I shifted back to 4th and all was well again. Went
back to 5th and grinding. So, I drove in to the office in 4th.
The Wrangler has about 145,000 miles on it if that helps. Any ideas?
Anyone know an decent and honest Jeep repair person near west central
Indiana? The dealerships here are not too good to work with.

Thanks!
Tim