My '87 Syncro has about 5K miles on a AA Transaxle rebuild.  When cold, you can plop it into gear with two fingers.  But after driving for awhile (hot or cold ambient temps) it is very difficult to put it into a gear.  Most notable is second, 'tho all gears offer a lot of resistance. 

Everything underneath is tight.  Shifting rod is well greased.  Tranny is full of MT-90. 

What could this be?

Thanks.

Tom Salicos
'87 Syncro Westy EG-33