Shifting Problem w/95 S-10 Transmission

I have a 1995 Chevy S10 with the 4.3L 5 speed manual transmission.
I've had my clutch, flywheel, Master and Slave cylinder, throw-out
bearings, etc..changed twice and still have the same problem. I tried
to tell the mechanic the second time that it's not the clutch parts
but possibly an internal problem inside the housing/case. Of course, I
don't know any better since I'm not a car mechanic but I do have 17
years fixing military aircraft so I am knowledgable of mechanical
devices. So I'm at my wits end in trying to determine the cause:

The main problem is shifting. With the clutch fully depressed,
shifting the gears is not smooth. I have to literally push/shove the
stick shift into gear. The problem is increased when I've been drving
for awhile or when the engine is hot. At this time, I literally have
to man-handle the stick-shift into gear.

Also, when I am fully stopped, with the clutch depressed, the car
still rolls as if it's still in gear. The "rolling" stops when I push
the clutch "through" the floor. I've bled this system until I've
literally replaced the fluid in the reservoir...

I cannot see any leaks from the transmission casing/housing, so I'm
not sure what to do next other than replace the transmission with a
rebuilt one, but even then I'm not 100 percent sure that will fix my
problem...

To me it seems like a possible flowing issue from the Master or Slave
cylinders going into the casing. Maybe a loose seal or something
simliar. I don't know of any vacumm lines as in an automatic transmissions. I admit that I do not know a lot about transmissions, so
any suggestions would be very helpful...