I am having the same problem on my 1995 GMC Sierra C 1500 2wd 5 speed manual transmission, I had the transmission rebuilt, bout a new clutch and slave cylinder. I've bled the clutch but am still having problems shifting into gear. When the truck is off it shifts perfectly into gear but when I turn it on it gets really hard to put it into gear. I don't see what the problem could be? Can somebody help me?