Yes moves in and out of gear smoothly as long as the engine rpm is fairly low, synchro is not that good, it crunches from 4th to 3rd, and from 3rd to 2nd, for a synchro box it isnt very good in the downshifting. Might be shot baulk rings? double clutching works.
The box has a new mainshaft and all gears and components on the shaft, except baulk rings. All bearings replaced. The chattering noise sounds like excessive backlash or something loose. Its got me beat. mainshaft nut tight to 100ft/lb. layshaft has no end play and new bearing front and back. Its an expensive mystery. Not sure if its worth persevering with.