2nd Gen Tranny problem

Any idea what would cause difficulty in downshifting? Just had tranny rebuilt- shifted OK at first, but is now very difficult to downshift, particularly 4th to 3rd (Turn 1 @ Summit). You can get it in eventually, but it feels like it takes a lifetime... Also v. easy to beat the synchro's on the 3-4 and 4-5 upshift.

I bled out the clutch cylinder- no air. Clutch plate & cover are several seasons old, not feeling any clutch slipping.

I'm at a loss- could the trans be the issue ? Worn/ weak clutch assy ??

Any thoughts or suggestions welcome.