94 1/2 ton 4WD transmission trouble.

[RShaips]

I just bought a 1994 GMC 1/2 ton 4wd with 118,000 miles on it from my neighbor real cheap. It is rusty and he had a transmission line rust thru and leak out fluid. When he tried to move it he couldn't. So he found the cracked line and cut it and replaced the section with a hose. So after he fixed it it will not shift into 3rd or overdrive. Shifts into neutral with no power and engine revs when you give it gas. Drop it into first or second and it works fine. That's why I got it so cheap. Any ideas of what happened? Thanks