Need 4-speed Help

Sounds like something is wrong with the transmission. You have changed,replaced, everything but the transmission so that's got to be the problem. Take the transmission to someone that has experience in rebuilding manual transmissions to have them look at it. Tell him exactly what you have done and told us that you did.

OR

Let it squeal until whatever it is tears up, burns up, catches on fire or explodes then you know where the problem was all along.

LOL!