picked up a rebuild t5 put it in and upshifts great nice and quit will not downshift into 2nd or first until below 10 mph. fresh royal purple fluid , 3,000 mi on motorsports clutch appears to be engaging and releasing ok.
took it to a actual transmission shop (witch I should have done originally) and he verified worn or improperly installed blocker rings,or shift dogs. I took that bad trans back to the other builder, got my money back. had Trans Colonial Auto give me one of there fully rebuilt units with a 1 yr warranty for the same price. problem fixed shifts like a dream.
Always be careful with the term rebuilt T5. There really is no such thing, because if you changed all the wear items in the transmission, you couldn't possibly turn a profit. I am over honest, and never use the term "rebuilt" when I turn a T5. I just say, it's "in good working order." I go in there, fix what's broken, and sell it. Pretty much what everone else does too.