No Bueno Shifto

[CA Victoria]

Working on a 35 trans, no prior history, it was disassembled, cleaned, & re assembled - This trans shift issue wasn’t apparent when I test run it on stands.
R & 1-2 up and down shift is great.
It will not shift into 3rd.
Removed tower & confirmed full movement, shifter & forks are good used. Full throw to all detents.
Shifted to 3rd with cover on, it won’t pull down as far as R. Took cover off while in 3rd and the cone doesn’t move forward far enough to engage the input shaft cone.
The cone and sleeve seemed ok when inspected.
I am stumped, I have over looked something with the assembly.
I cannot think of another option than to pull the transmission to troubleshoot the problem.........
I will borrow another early tower to compare movement.

Any thoughts from the trans gurus? .....