Transmission troubles

I have a '93 Mighty Max 5spd 2wd.

My problems started with a humming noise and vibration while accelerating up to about 55mph, also i could feel a definite drag while driving compared to before.

I changed U-joints thinking that was problem after i found one slightly worn bearing. I also replaced leaking extension shaft seal, drained and refilled with new 80-90W gear oil. However it did not fix problem.

Same day after test driving problem was still there. While driving home from test drive shifting from 3rd to 4th suddenly the shift shift went floppy and would not engage out of 3rd or into any other gears.

So stuck in 3rd and cannot shift out, but clutch will still engage and roll forward in 3rd gear. The stick shift feels broken off, extremely floppy.?

Any ideas??

Ok well i found the problem immediately when i pulled the shift boot back and went to remove the stick shift, the 3 bolts that hold the stopper plate down were backing out and the lever had popped out. The lever bushing looks slightly damaged/cracked and i didn't find any gaskets between the stopper plate on up to the control lever. any ideas where i can get a new lever bushing or gaskets?

I have that nylon bushing for the shifter if you still need it.