It does have hydraulic lifters.
Did you run it long? did they quiet down if you did?
What's the oil like? New filter?
Have you shined a light into the oil filler hole to assess the sludge buildup?
A bleed is a b*@ch.
With the clutch working as it does, the pumping shoulda made a difference if it were an air issue.
So, when clutch was first replaced, you didn't have this issue?
It just cropped up afterwards?
Dude!!!
Start the son of a b*@ch and shift into reverse!!! Report back. 2 minute job.
Beating this dead horse about fluids doesn't get to the root issue.
You're making it very difficult for a bunch of really good guys to help you.
IIRC, the BA-10 had conical aluminum synchros and that was part of the problem.
Just a poor design. Not a problem with reacting to fluid.
My buddies at JeepTech recommended an additive to help with the shifting, but that was over 30 years ago. I'll try to hunt it down.